uva 10154 Weights and Measures(01双肩包)
uva 10154 Weights and Measures(01背包)
题目连接:10154 - Weights and Measures
题目大意:有若干只乌龟,每只乌龟有重量和负重两个属性,现在求这若干只乌龟最多可以叠多少层。
解题思路:01背包的变形, 以负重值作为背包的大小, 层数为所求dp值, 每次以min(当前可负重值-乌龟的重量, 乌龟的负重)考虑。
include <stdio.h> #include <string.h> #include <algorithm> using namespace std; const int N = 10005; int min(int a, int b) { return a > b ? b : a; } struct state { int w; int s; }tmp[N]; int n, dp[N * 1000]; bool cmp (const state& a, const state& b) { return a.s > b.s; } void Init() { n = 0; memset(tmp, 0, sizeof(tmp)); memset(dp, 0, sizeof(dp)); while (scanf("%d%d", &tmp[n].w, &tmp[n].s) == 2) n++; sort(tmp, tmp + n, cmp); } int solve() { int Max = tmp[0].s, t; for (int i = 0; i < n; i++) { for (int j = tmp[i].w; j <= Max; j++) { if (dp[j]) { t = min(j - tmp[i].w, tmp[i].s); if (dp[t] < dp[j] + 1) dp[t] = dp[j] + 1; } } t = tmp[i].s - tmp[i].w; if (dp[t] == 0) dp[t] = 1; } int cur = 0; for (int i = 0; i <= Max; i++) { if (cur < dp[i]) cur = dp[i]; } return cur; } int main() { Init(); printf("%d\n", solve()); return 0; }