HDU 3401 Trade【单调队列+dp】

来源：互联网发布：linux修改分辨率命令编辑：程序博客网时间：2024/05/22 19:16

题意：已知股票每天的买入和卖出价格、买入上限和卖出上限以及最多能持有的股票数，问n天后的最大收益是多少。

#include <iostream>#include <cstring>#include <cstdio>#include <algorithm>#include <cmath>using namespace std;const int oo = 1 << 30;const int maxn = 2010;int tcase;int t, maxp, w;int ap[maxn], bp[maxn];int as[maxn], bs[maxn];int dp[maxn][maxn];int head, tail;int q[maxn][2];void DP(){    for (int i = 0; i < maxn; ++i) {        for (int j = 0; j < maxn; ++j) {            dp[i][j] = -oo;        }    }    // 前w+1天只能买入     for (int i = 1; i <= w + 1; ++i) {        for (int j = 0; j <= min(maxp, as[i]); ++j) {            dp[i][j] = -ap[i] * j;        }    }    for (int i = 2; i <= t; ++i) {        /*for (int j = 0; j <= maxp; ++j) {            dp[i][j] = max(dp[i][j], dp[i-1][j]);        }        if (i <= w + 1) continue;        */        head = tail = 0;        for (int j = 0; j <= maxp; ++j) {            dp[i][j] = max(dp[i][j], dp[i-1][j]);            if (i <= w + 1) continue;            while (head < tail && q[tail-1][1] <= dp[i-w-1][j] + ap[i] * j) {                tail--;            }            q[tail][0] = j;            q[tail++][1] = dp[i-w-1][j] + ap[i] * j;            while (head < tail && j - q[head][0] > as[i]) {                head++;            }            dp[i][j] = max(dp[i][j], q[head][1] - ap[i] * j);        }        head = tail = 0;        for (int j = maxp; j >= 0; --j) {            if (i <= w + 1) continue;            while (head < tail && q[tail-1][1] <= dp[i-w-1][j] + bp[i] * j) {                tail--;            }            q[tail][0] = j;            q[tail++][1] = dp[i-w-1][j] + bp[i] * j;            while (head < tail && q[head][0] - j > bs[i]) {                head++;            }            dp[i][j] = max(dp[i][j], q[head][1] - bp[i] * j);        }    }    int ans = -oo;    for (int i = 0; i <= maxp; ++i) {        ans = max(ans, dp[t][i]);    }    printf("%d\n", ans);}int main(){    scanf("%d", &tcase);    while (tcase--) {        scanf("%d%d%d", &t, &maxp, &w);        for (int i = 1; i <= t; ++i) {            scanf("%d%d%d%d", &ap[i], &bp[i], &as[i], &bs[i]);        }        DP();    }    return 0;}