uvalive3983Robtruck

题意：有n个垃圾，第i个垃圾坐标为(xi，yi)。有一个机器人按照编号从小到大哦捡起所有的垃圾并扔进垃圾桶，垃圾桶再远点。机器人手中垃圾总重量不能超过C，两点之间的距离为曼哈顿距离，求机器人行走的最短总路程

分析：d[i]=min{d[j]+dist2origin(j+1)+dist(j+1,i)+dist2origin(i)|j<=i, w(j+1,i)<=c}

里面可以写成函数f以简化计算

代码：

#include <stdio.h>
#include <algorithm>
using namespace std;
const int MAXN = 100000 + 10;
int x[MAXN], y[MAXN];
int total_dist[MAXN], total_weight[MAXN], dist2origin[MAXN];
int q[MAXN], d[MAXN];
#define DEBUG
int func(int i){
    return d[i]-total_dist[i+1]+dist2origin[i+1];
}

int main(){
#ifndef DEBUG
    freopen("in.txt", "r", stdin);
#endif
    int T, c, n, w, front, rear;
    scanf("%d", &T);
    while(T--){
        scanf("%d%d", &c, &n);
        total_dist[0] = total_weight[0] = x[0] = y[0] = 0;
        int i;
        for(i=1; i<=n; i++){
            scanf("%d%d%d", &x[i], &y[i], &w);
            dist2origin[i] = abs(x[i])+abs(y[i]);
            total_dist[i] = total_dist[i-1] + abs(x[i]-x[i-1])+abs(y[i]-y[i-1]);
            total_weight[i] = total_weight[i-1] + w;
        }
        front = rear = 1;
        for(i=1; i<=n; i++){
            while(front<=rear && total_weight[i]-total_weight[q[front]]>c) front++;
            d[i]=func(q[front])+total_dist[i]+dist2origin[i];
            while(front<=rear && func(i)<=func(q[rear])) rear--;
            q[++rear] = i;
        }
        printf("%d\n", d[n]);
        if(T>0) printf("\n");
    }
    return 0;
}

今天感觉做题目不很在状态，直接看了训练指南上的分析。。