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Knapsack Problem CodeChef Solution

Problem -Knapsack Problem CodeChef Solution

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Knapsack Problem CodeChef Solution in C++14

// Ref : _krugarr_

#include"bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double lld;
const int W = 1e7+10;

#define     EPS                  1e-9
#define     INF                  (int)1e9
#define     MOD                  1000000007

#define     ff                   first
#define     ss                   second
#define     tab                  "\t"
#define     endl                 "\n"
#define     gcd(x,y)             __gcd(x,y)
#define     lcm(x,y)             ( (x*y)/__gcd(x,y) )
#define     pb                   emplace_back
#define     gc                   getchar_unlocked
#define     eraseAt(a,index)     (a).erase( (a).begin() + index )
#define     all(a)               (a).begin(), (a).end()
#define     uniq(a)              (a).erase( unique(all(a)), (a).end() )
#define     repItr(i,a)          for(auto i: (a))
#define     rep(i,a,b)           for(ll i = a; i < b; i++)                 
#define     rrep(i,a,b)          for(ll i = a; i >= b; i--)                

#define     countLZ(x)           __builtin_clz(x)                          // returns the count of leading zeros in binary of a data upto first set(1) bit
#define     countTZ(x)           __builtin_ctz(x)                          // returns the count of trailing zeros in binary of a data from last set(1) bit
#define     checkbit(n,b)        ( (n >> b)&1 )                            
#define     parityCheck(x)       __builtin_parity(x)                       // returns 1(true) if odd number of set bits present in int, long data
#define     setbitCount(x)       __builtin_popcount(x)                     // returns the number of one’s(set bits) in binary of an int, long data
#define     PI                   3.1415926535897932384626433832795

#ifndef ONLINE_JUDGE
#define debug(x) cerr << #x <<" "; _print(x); cerr << endl;
#else
#define debug(x)
#endif

void    _print(ll t)       {cerr << t;}
void    _print(int t)      {cerr << t;}
void    _print(string t)   {cerr << t;}
void    _print(char t)     {cerr << t;}
void    _print(lld t)      {cerr << t;}
void    _print(double t)   {cerr << t;}
void    _print(ull t)      {cerr << t;}

template <class T, class V>  void _print(pair <T, V> p);
template <class T>           void _print(vector <T> v);
template <class T>           void _print(set <T> v);
template <class T, class V>  void _print(map <T, V> v);
template <class T>           void _print(multiset <T> v);
template <class T, class V>  void _print(pair <T, V> p) {cerr << "{"; _print(p.ff); cerr << ","; _print(p.ss); cerr << "}";}
template <class T>           void _print(vector <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T>           void _print(set <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T>           void _print(multiset <T> v) {cerr << "[ "; for (T i : v) {_print(i); cerr << " ";} cerr << "]";}
template <class T, class V>  void _print(map <T, V> v) {cerr << "[ "; for (auto i : v) {_print(i); cerr << " ";} cerr << "]";}

/*======================================================== End_Of_Header ========================================================*/

inline void io(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);        
    cout.tie(NULL);       
    #ifndef ONLINE_JUDGE  
        freopen("input_6.txt","r",stdin);
        freopen("output_6.txt","w",stdout);
    #endif
}

template <typename T> using V = vector<T>;
template <typename T> V<T> prefixSum(const V<T> &v) {
    int n = v.size(); V<T> ret(n + 1);
    rep(i, 0, n) ret[i + 1] = ret[i] + v[i]; return ret;
} 

inline int mod_32(int x, int divisor) {int m = x % divisor; return m + ((m >> 31) & divisor);}
inline ll mod_64(ll x, ll divisor) {ll m = x % divisor; return m + ((m >> 63) & divisor);}

// ll input[W]; ll Sum_Of[W];

bool isPowerOf2(ll n){ if(n&(n-1)) return false; else return true; }

/*======================================================= End_Of_Utilities =======================================================*/
void solve(){
    ll n,k,i,ans=0,b=0,c=1,j,x,w,c1,c2;
    cin>>n;
    vector<long> v2,v1;
    for(i=1;i<=n;i++){
        cin>>w>>x;
        if(w==1) v1.push_back(x);
        else v2.push_back(x);
        b+=w;
    }
    vector<vector<long>> dp(b+1,vector<long>(3));
    dp[0][0]=0; dp[0][1]=0; dp[0][2]=0;
    sort(v1.begin(),v1.end(),greater<long>());
    sort(v2.begin(),v2.end(),greater<long>());
    for(i=1;i<=b;i++){
        c1=0; c2=0;
        if(i>=1){
            c1=dp[i-1][0];
            j=dp[i-1][1];
            if(j<v1.size()) c1=c1+v1[j];
        }
        if(i>=2){
            c2=dp[i-2][0];
            j=dp[i-2][2];
            if(j<v2.size()) c2=c2+v2[j];
        }
        if(c1>=c2){
            dp[i][0]=c1; dp[i][1]=dp[i-1][1]+1;
            dp[i][2]=dp[i-1][2];
        }
        else{
            dp[i][0]=c2; dp[i][1]=dp[i-2][1];
            dp[i][2]=dp[i-2][2]+1;
        }
        cout<<dp[i][0]<<" ";
    }
    cout<<"\n";
}
int main(){
    io();
    ll tc = 1;
  while(tc-->0){
        solve();
    }
    return 0;
}

Knapsack Problem CodeChef Solution in PYTH 3


test = False
N = int(input())
ones = []
twos = []

for i in range(N):
    W, C = map(int, input().strip().split(' '))
    if test: print('W, C = ', W, C)
    if W == 1:
        ones.append(C)
    else:
        twos.append(C)

max_weight = len(ones) + 2 * len(twos)

if len(ones) >= 1:
    ones.append(0)
    ones.sort(reverse=True)

    even_twos = twos.copy()
    odd_twos = twos.copy()

    for i in range(1, len(ones)):
        if i % 2 == 1:
            even_twos.append(ones[i] + ones[i - 1])
        else:
            odd_twos.append(ones[i] + ones[i - 1])

    even_twos = sorted(even_twos)
    odd_twos = sorted(odd_twos)

    res = [0, ones[0]]

    for w in range(2, max_weight + 1):
        if w % 2 == 0:
            temp = even_twos.pop()
        else:
            temp = odd_twos.pop()
        res.append(res[w - 2] + temp)

else:
    res = [0, 0]
    twos = sorted(twos)
    for w in range(2, max_weight + 1):
        temp = 0
        if w % 2 == 0:
            temp = twos.pop()
        res.append(max(res[w - 2] + temp, res[w - 1]))
res.pop(0)
print(*res,sep = ' ')

Knapsack Problem CodeChef Solution in C

#include<stdio.h>
#include<stdlib.h>

long long int max(long long int a, long long int b)
{
    return (a>b)?a:b;
}

int compare_long_long_ints_desc(const void* a, const void* b)
{
    return *((const long long int*)(b)) - *((const long long int*)(a));
}

int main(void) {
	long long int N;
	scanf("%lld", &N);
	long long int* I[3];
	long long int Isize[3] = {};
	I[2] = malloc(sizeof(long long int) * N);
	I[1] = malloc(sizeof(long long int) * N);
	long long int M = 0;
	for(long long int i = 0; i < N; i++)
	{
	    long long int W;
	    long long int C;
	    scanf("%lld %lld", &(W), &(C));
	    M += W;
	    I[W][Isize[W]++] = C;
	}
	
	qsort(I[1], Isize[1], sizeof(long long int), compare_long_long_ints_desc);
	qsort(I[2], Isize[2], sizeof(long long int), compare_long_long_ints_desc);
	
	/*for(long long int i = 0; i < Isize[1]; i++)
	    printf("%lld ", I[1][i]);
	printf("\n");
	
	for(long long int i = 0; i < Isize[2]; i++)
	    printf("%lld ", I[2][i]);
	printf("\n");*/
	
	long long int* res = calloc(sizeof(long long int), (M+1));
	
	long long int* i[3];
	i[1] = calloc(sizeof(long long int), (M+1));
	i[2] = calloc(sizeof(long long int), (M+1));
	
	for(long long int m = 1; m <= M; m++)
	{
	    /*res[m] = 0;
	    i[1][m] = 0;
	    i[2][m] = 0;*/
	    res[m] = res[m-1];
	    i[1][m] = i[1][m-1];
	    i[2][m] = i[2][m-1];
	    if(m >= 1 && i[1][m-1] < Isize[1])
	    {
	        if(res[m] < res[m-1] + I[1][i[1][m-1]])
	        {
	            res[m] = res[m-1] + I[1][i[1][m-1]];
	            i[1][m] = i[1][m-1] + 1;
	            i[2][m] = i[2][m-1];
	        }
	    }
	    if(m >= 2 && i[2][m-2] < Isize[2])
	    {
	        if(res[m] < res[m-2] + I[2][i[2][m-2]])
	        {
	            res[m] = res[m-2] + I[2][i[2][m-2]];
	            i[1][m] = i[1][m-2];
	            i[2][m] = i[2][m-2] + 1;
	        }
	    }
	}
	    
	free(I[2]);
	free(I[1]);
	free(i[2]);
	free(i[1]);
	
	for(long long int i = 1; i <= M; i++)
	    printf("%lld ", res[i]);
	printf("\n");
	
	free(res);
	return 0;
}

Knapsack Problem CodeChef Solution in JAVA

import java.io.*;
import java.util.*;

class c{
	public static void main(String [] arg){
		FastReader f = new FastReader();
		ArrayList<Integer> w1 = new ArrayList<>();
		ArrayList<Integer> w2 = new ArrayList<>();
		int n = f.nextInt();
		for(int i=0;i<n;i++){
			if (f.nextInt()==1){
				w1.add(f.nextInt());
			}
			else{
				w2.add(f.nextInt());
			}
		}
		Collections.sort(w1,Collections.reverseOrder());
		Collections.sort(w2,Collections.reverseOrder());
		
	        int i=0,j=0;
	        long ans=0;
	        int cw=0;
	        long w = w1.size()+2*w2.size();
	
	        for(int k=1;k<=w;k++){
	            long ans1=ans, ans2=ans;
	
	            if(k-cw==1) {
	                if (i < w1.size()) ans1 += w1.get(i);
	                if (i >= 1 && j < w2.size()) ans2 = ans2 - w1.get(i - 1) + w2.get(j);
	
	                if (ans1>ans && ans1>=ans2) {
	                    i++;
	                    ans = ans1;
	                    cw++;
	                } else if (ans2 > ans) {
	                    i--;
	                    j++;
	                    ans = ans2;
	                    cw++;
	                }
	            }
	
	            else if(j<w2.size()){ans += w2.get(j); j++; cw+=2;}
	
	            System.out.print(ans + " ");
	        }
	        
	}

	static class FastReader{
		
		StringTokenizer st=new StringTokenizer("");
		BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
		
		String next() {
			while(!st.hasMoreTokens()) 
				try {
					st=new StringTokenizer(br.readLine());
				}
			   catch(IOException e){
				   e.printStackTrace();
			   }
			return st.nextToken();
		}
		
		int nextInt() {
			return Integer.parseInt(next());
		}
		
		long nextLong() {
			return Long.parseLong(next());
		}
		}
}

Knapsack Problem CodeChef Solution in PYPY 3

# cook your dish here
import sys
input=sys.stdin.buffer.readline


n=int(input())
w1=[]
w2=[]
# c=[0]
for i in range(n):
    wi,ci=[int(x) for x in input().split()]
    if wi == 2 :
        w2.append(ci)
    else:
        w1.append(ci)

w1.sort()
w2.sort()


w1o=w1.copy()
w2o=w2.copy()

m=len(w2)*2 + len(w1)

curr=0
ans=[0 for i in range(m+1)]
for w in range(2,m+1,2):
    cost1=0
    cost2=0
    flag=0
    if len(w2) >=1 :
        cost1 = w2[-1]
    
    if len(w1) >=2 :
        cost2=w1[-1]+w1[-2]
        flag=2
    elif len(w1) >=1 :
        cost2 = w1[-1]
        flag=1
    
    if cost1 > cost2:
        curr+=cost1
        ans[w] = curr
        w2.pop()
    else:
        curr+=cost2
        ans[w] = curr
        while flag > 0:
            w1.pop()
            flag-=1

# print(ans)


curr=0
if len(w1o) >=1:
    curr=w1o.pop()
    ans[1]=curr

ans[1]=curr
w1=w1o
w2=w2o
for w in range(3,m+1,2):
    cost1=0
    cost2=0
    flag=0
    if len(w2) >=1 :
        cost1 = w2[-1]
    
    if len(w1) >=2 :
        cost2=w1[-1]+w1[-2]
        flag=2
    elif len(w1) >=1 :
        cost2 = w1[-1]
        flag=1
    
    if cost1 > cost2:
        curr+=cost1
        ans[w] = curr
        w2.pop()
    else:
        curr+=cost2
        ans[w] = curr
        while flag > 0:
            w1.pop()
            flag-=1

print(" ".join([str(c) for c in ans[1:]]))

Knapsack Problem CodeChef Solution in PYTH

n = int(raw_input())
f = [[], []] 
total = 0 
for _ in xrange(n):
    w, c = map(int, raw_input().split())
    f[w%2] += c, 
    total += w
ans = [0] * (total + 1)
f = [sorted(i, reverse = 1) for i  in f]
pairs = [[] for _ in xrange(total + 1)]
pairs[0] = (0, 0)
def update(i, s, p):
    if s > ans[i]:
        ans[i] = s 
        pairs[i] = p
    
for e in xrange(1,total+1):
    ans[e] = ans[e-1] 
    i,j = pairs[e] = pairs[e-1]
    update(e, ans[e-1] + sum(f[1][j:j+1]) , (i, j + 1))      #pick the next 1 one
    if e >= 2:
        i,j = pairs[e-2]
        update(e, ans[e-2] + sum(f[1][j:j+2]) , (i, j + 2))  #pick the next 2 ones
        update(e, ans[e-2] + sum(f[0][i:i+1])  , (i+1, j ))  #pich the next two
    print ans[e],
    
    
#weight chỉ có 1 và 2, sort weight 1 và 2 theo giá trị giảm dần của values 
#think of w is a collections of 1s and 2s, suppose w = 1 * i + 2 * j then we will pick the first i 1s and the first js 2th 
#=>linear algorithm, at each index store the pair (i,j) which make w has maximum value
#3 case:
#from w-1, pick the next one
#from w - 2, pich the next 2 ones
#from w-2, pick the next two
#just update and select the maximum value

Knapsack Problem CodeChef Solution in C#

using System;
using System.Collections.Generic;

public class Test
{
    public static void Main()
    {
        List<ulong> one = new List<ulong>();
        List<ulong> two = new List<ulong>();
        ulong[] ans = new ulong[200001];
        int N = int.Parse(System.Console.ReadLine());
        int W=0;
        for(int i = 0; i<N; i++)
        {
            string[] s = System.Console.ReadLine().Split(' ');
            
            int w = int.Parse(s[0]);
            
            ulong cost  = UInt64.Parse(s[1]);
            if(w==1) one.Add(cost);
            else two.Add(cost);
            W+=w;
            
        }
        one.Sort();
        two.Sort();
        List<ulong> oneD = new List<ulong>(one);
        List<ulong> twoD = new List<ulong>(two);
        ulong current = 0;
        for(int i=2;i<=W;i+=2)
        {
            ulong cost1=0,cost2=0;
            int flag = 0;
            if(two.Count>=1) cost2 = two[two.Count-1];
            if(one.Count>=2) { cost1 = one[one.Count-1];cost1+= one[one.Count-2];
                                flag = 2;}
                                else if(one.Count>=1) { cost1 = one[one.Count-1];flag =1;}
            if(cost2>cost1) 
                { 
                    current+=cost2;two.RemoveAt(two.Count-1);
                }
            else { current+=cost1;
                    if(flag==2) {
                    one.RemoveAt(one.Count-1);
                    one.RemoveAt(one.Count-1);}
                    else {
                        one.RemoveAt(one.Count-1);}
                    }
            ans[i]+=current;     
            
        }
        one = oneD;
        two = twoD;
        //Console.Error.WriteLine(one.Count + " " + two.Count);
        current = 0;
        if(one.Count >=1) 
        {
            current+=one[one.Count-1];
            one.RemoveAt(one.Count-1);
            ans[1]=current;
        }
        for(int i=3;i<=W;i+=2)
        {
            ulong cost1=0,cost2=0;
            int flag = 0;
            if(two.Count>=1) cost2 = two[two.Count-1];
            if(one.Count>=2) { cost1 = one[one.Count-1];cost1+= one[one.Count-2];
                                flag = 2;}
                                else if(one.Count>=1) { cost1 = one[one.Count-1];flag =1;}
            //Console.Error.WriteLine(two.Count + " " + flag);
            if(cost2>cost1) 
                { 
                    current+=cost2;two.RemoveAt(two.Count-1);
                }
            else { current+=cost1;
                    
                    if(flag==2) {
                    one.RemoveAt(one.Count-1);
                    one.RemoveAt(one.Count-1);
                
                    }
                    else {
                        one.RemoveAt(one.Count-1);}
                    }
            ans[i]+=current;     
            
        }
        for(int i = 1;i<=W ; i++)
        {
            if(i>1) System.Console.Write(" ");
            System.Console.Write(ans[i]);
        }
        
    }
}

Knapsack Problem CodeChef Solution in GO

package main

import (
	"sort"
	"bufio"
	"os"
	"fmt"
)

func readInt(bytes []byte, from int, val *int) int {
	i := from
	tmp := 0
	for i < len(bytes) && bytes[i] != ' ' {
		tmp = tmp*10 + int(bytes[i]-'0')
		i++
	}
	*val = tmp
	return i
}

func readNum(scanner *bufio.Scanner) (a int) {
	scanner.Scan()
	readInt(scanner.Bytes(), 0, &a)
	return
}

func readTwoNums(scanner *bufio.Scanner) (a int, b int) {
	scanner.Scan()
	x := readInt(scanner.Bytes(), 0, &a)
	readInt(scanner.Bytes(), x+1, &b)
	return
}

func readNNums(scanner *bufio.Scanner, n int) []int {
	res := make([]int, n)
	x := -1
	scanner.Scan()
	for i := 0; i < n; i++ {
		x = readInt(scanner.Bytes(), x+1, &res[i])
	}
	return res
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	n := readNum(scanner)
	W := make([]int, n)
	C := make([]int, n)
	for i := 0; i < n; i++ {
		W[i], C[i] = readTwoNums(scanner)
	}
	res := solve(n, W, C)
	fmt.Printf("%d", res[0])
	for i := 1; i < len(res); i++ {
		fmt.Printf(" %d", res[i])
	}
	fmt.Println()
}

func solve(n int, W []int, C []int) []int64 {
	vc := make([]int, n)
	i, j := 0, n-1
	for k := 0; k < n; k++ {
		if W[k] == 1 {
			vc[i] = C[k]
			i++
		} else {
			vc[j] = C[k]
			j--
		}
	}

	sort.Ints(vc[:i])
	sort.Ints(vc[j+1:])

	var S int
	for a := 0; a < n; a++ {
		S += W[a]
	}
	res := make([]int64, S+1)

	var cur int64
	for w, u, v := 2, n-1, i-1; w <= S; w += 2 {
		if u == j && v < 0 {
			break
		}
		var x, y int64
		if u > j {
			x = int64(vc[u])
		}
		if v > 0 {
			y = int64(vc[v] + vc[v-1])
		} else if v == 0 {
			y = int64(vc[v])
		}
		if x > y {
			cur += x
			u--
		} else {
			cur += y
			v--
			v--
		}
		res[w] = cur
	}
	cur = 0
	if i > 0 {
		cur = int64(vc[i-1])
		i--
	}
	res[1] = cur
	for w, u, v := 3, n-1, i-1; w <= S; w += 2 {
		if u == j && v < 0 {
			break
		}
		var x, y int64
		if u > j {
			x = int64(vc[u])
		}
		if v > 0 {
			y = int64(vc[v] + vc[v-1])
		} else if v == 0 {
			y = int64(vc[v])
		}
		if x > y {
			cur += x
			u--
		} else {
			cur += y
			v--
			v--
		}
		res[w] = cur
	}

	return res[1:]
}
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