題目鏈接:點擊打開鏈接
題意:
取款機的問題;
有 n 種錢;
每種錢有 v[i] 的價值;
每種錢有 w[i] 張;
問給定要取得錢 cash 之後能從取款機最多取多少錢;
理解:
多重揹包;
直接套模板;
遞推式:dp[i] = max(dp[i], dp[i - mul * v[i]] + mul * v[i]);
其中的值根據代碼定義;
代碼如下:
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <queue>
#include <stack>
using namespace std;
typedef long long LL;
typedef pair<int, int> PII;
const int MIN_INF = 1e-7;
const int MAX_INF = (1e9) + 7;
#define X first
#define Y second
int dp[222222];
int v[111], w[111];
int main() {
int cash, n;
while (cin >> cash >> n) {
for (int i = 0; i < n; ++i) {
cin >> w[i] >> v[i];
}
memset(dp, 0, sizeof(dp));
for (int i = 0; i < n; ++i) {
int num = w[i];
for (int k = 1; num > 0; k <<= 1) {
int mul = min(k, num);
for (int j = cash; j >= mul * v[i]; --j) {
dp[j] = max(dp[j], dp[j - mul * v[i]] + mul * v[i]);
}
num -= k;
}
}
cout << dp[cash] << endl;
}
return 0;
}