Luo Gu P1833 - Sakura

Title Description

P1833 cherry

Solution: a combination of backpack

Binary decomposition

#include <bits/stdc++.h>

using namespace std;

int nx, ny, ex, ey, n, tp;
int t[10005], c[10005], p[10005];
int cost[1000005], value[100005];
int dp[1010];

void binary_split()
{
    for(int i=1;i<=n;i++)
    {
        int k = 1;
        while(p[i])
        {
            cost[++tp] = k*t[i];
            value[tp] = k*c[i];
            p[i] -= k;
            k *= 2;
            if(p[i]<k)
            {
                cost[++tp] = t[i]*p[i];
                value[tp] = c[i]*p[i];
                break;
            }
        }
    }
}

int main()
{
    scanf("%d:%d%d:%d%d",&nx,&ny,&ex,&ey,&n);
    int ttime = (ex*60+ey)-(nx*60+ny);
    for(int i=1;i<=n;i++)
    {
        scanf("%d%d%d",&t[i],&c[i],&p[i]);
        if(!p[i]) p[i] = 999999;
    }
    binary_split();
    for(int i=1;i<=tp;i++)
        for(int j=ttime;j>=cost[i];j--)
            dp[j] = max(dp[j], dp[j-cost[i]]+value[i]);
    printf("%d", dp[ttime]);
    return 0;
}