c_cpp 子集和问题| DP-25

Posted 2021-05-14

//https://www.geeksforgeeks.org/subset-sum-problem-dp-25/
#include <iostream>
using namespace std;

bool subset  (int set[], int n, int sum) {
    bool dp[sum+1][n+1];

    for (int i=0; i<=n; i++)
        dp[0][i]= 1;
    for (int i=1; i<=sum; i++)
        dp[i][0]= 0;

    for (int i=1; i<= sum; i++) {
        for (int j=1; j<=n; j++) {
            if (i < set[j-1])
                dp[i][j]= dp[i][j-1];
            else
                dp[i][j]= dp[i][j-1] || dp[i-set[j-1]][j-1];
        }
    }
    return dp[sum][n];
}

int main() {
    int n, sum;
    cin>> n>> sum;
    int a[n];
    for (int i=0;i<n;i++)
        cin>>a[i];

    if (subset(a,n,sum))
        cout<< "Sum exists!";
    else
        cout<< "No such sum!";
}