SDNUOJ 1539 恰当选择DP对象

Description

T组输入样例

N个物品，W最大承重

每个物品都有对应的w[i], v[i]

求总重不超W时最大价值V

01背包选择价值作为DP对象，详见小白书Page61

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;

const int INF = 0x3f3f3f3f;
int dp[505][5005];
int w[505], v[505];
int N, W;

int main()
{
    int t;
    cin >> t;
    while(t--)
    {
        scanf("%d%d", &N, &W);
        for(int i = 1; i <= N; ++i)
            scanf("%d%d", &w[i], &v[i]);
        memset(dp, INF, sizeof(dp));
        dp[0][0] = 0;
        for(int i = 1; i <= N; ++i)
            for(int j = 0; j <= 5000; ++j)
            {
                if(j < v[i])
                    dp[i][j] = dp[i - 1][j];
                else
                    dp[i][j] = min(dp[i - 1][j], dp[i - 1][j - v[i]] + w[i]);
            }
        int ans = 0;
        for(int i = 0; i <= 5000; ++i)
        {
            if(dp[N][i] <= W)
                ans = i;
        }
        cout << ans << '\n';
    }
    return 0;
}