ZOJ 3331 Process the Tasks

Posted 2020-06-19 Fighting Heart

双塔DP。

#include<cstdio>
#include<cstring>
#include<queue>
#include<string>
#include<algorithm>
#include<map>
#include<iostream>
using namespace std;

const int maxn=100+50;
int T,n;
int dp[maxn][2*maxn];
int a[maxn],b[maxn];

void init()
{
    for(int i=1;i<=n;i++)
        for(int j=0;j<=200;j++)
            dp[i][j]=0x7fffffff;
}

void read()
{
    scanf("%d",&n);
    for(int i=1;i<=n;i++) scanf("%d%d",&a[i],&b[i]);
}

void work()
{
    dp[1][a[1]+100]=dp[1][0-b[1]+100]=0;

    for(int i=2;i<=n;i++)
    {
        for(int j=0;j<=200;j++)
        {
            if(dp[i-1][j]==0x7fffffff) continue;
            int tmp=j-100;
            if(tmp>=0)
            {
                dp[i][a[i]+100]=min(dp[i][a[i]+100],dp[i-1][j]+tmp);
                if(b[i]>=tmp) dp[i][tmp-b[i]+100]=min(dp[i][tmp-b[i]+100],dp[i-1][j]+tmp);
                else if(b[i]<tmp) dp[i][tmp-b[i]+100]=min(dp[i][tmp-b[i]+100],dp[i-1][j]+b[i]);
            }

            else if(tmp<0)
            {
                tmp=-tmp;
                if(dp[i-1][j]+tmp<dp[i][0-b[i]+100]) dp[i][0-b[i]+100]=min(dp[i][0-b[i]+100],dp[i-1][j]+tmp);
                if(a[i]<=tmp) dp[i][a[i]-tmp+100]=min(dp[i][a[i]-tmp+100],dp[i-1][j]+a[i]);
                else if(a[i]>tmp) dp[i][a[i]-tmp+100]=min(dp[i][a[i]-tmp+100],dp[i-1][j]+tmp);
            }
        }
    }

    int ans=0x7fffffff;
    for(int j=0;j<=200;j++)
    {
        if(dp[n][j]==0x7fffffff) continue;
        ans=min(ans,dp[n][j]+abs(j-100));
    }
    printf("%d\n",ans);
}

int main()
{
    scanf("%d",&T);
    while(T--)
    {
        read();
        init();
        work();
    }
    return 0;
}