bzoj1855: [Scoi2010]股票交易

背包

感觉省选怎么会考这么简单的东西呢 无聊去网上搜了一下 发现原来正解是单调队列来优化呀

不过带个log问题也不大

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>

using namespace std;

void setIO(const string& a) {
    freopen((a+".in").c_str(), "r", stdin);
    freopen((a+".out").c_str(), "w", stdout);
}

const int N = 2010, INF = 0x3f3f3f3f;

int f[N][N], g[N];

template<typename Q> void maxit(Q& x, const Q& y) {
    if(x < y) x = y;
}

int main() {
    
    int n, maxp, w, ap, bp, as, bs;
    scanf("%d%d%d", &n, &maxp, &w);
    
    memset(f, -0x3f, sizeof f);
    
    f[1][0] = 0;
    
    for(int sum, ok, k, i = 1; i <= n; i++) {
        scanf("%d%d%d%d", &ap, &bp, &as, &bs);
        memcpy(g, f[i], sizeof g);
        int tmr = min(i + 1 + w, n + 1);
        for(ok = 1, sum = 0, k = 1; ok; k <<= 1) {
            if(sum + k <= as) sum += k;
            else k = as - sum, ok = 0;
            for(int j = maxp; j >= 0; j--) if(g[j] > -INF) {// buy
                if(j + k <= maxp) maxit(g[j + k], g[j] - ap * k);
            }
        }
//        memcpy(g, f[i], sizeof g);
        for(ok = 1, sum = 0, k = 1; ok; k <<= 1) {
            if(sum + k <= bs) sum += k;
            else k = bs - sum, ok = 0;
            for(int j = 0; j <= maxp; j++) if(g[j] > -INF) {// sell
                if(j - k >= 0) maxit(g[j - k], g[j] + bp * k);
            }
        }
        for(int j = 0; j <= maxp; j++) {
            maxit(f[i + 1][j], f[i][j]);
            maxit(f[tmr][j], g[j]);
        }        
    }
    int ans = 0;
    for(int i = 0; i <= maxp; i++) ans = max(ans, f[n + 1][i]);
    printf("%d
", ans);
    
    return 0;
}