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：

View Code

 1 #include <stdio.h>
 2 #include <algorithm>
 3 using namespace std;
 4 const int MAXN = 100000 + 10;
 5 int x[MAXN], y[MAXN];
 6 int total_dist[MAXN], total_weight[MAXN], dist2origin[MAXN];
 7 int q[MAXN], d[MAXN];
 8 #define DEBUG
 9 int func(int i){
10     return d[i]-total_dist[i+1]+dist2origin[i+1];
11 }
12 
13 int main(){
14 #ifndef DEBUG
15     freopen("in.txt", "r", stdin);
16 #endif
17     int T, c, n, w, front, rear;
18     scanf("%d", &T);
19     while(T--){
20         scanf("%d%d", &c, &n);
21         total_dist[0] = total_weight[0] = x[0] = y[0] = 0;
22         int i;
23         for(i=1; i<=n; i++){
24             scanf("%d%d%d", &x[i], &y[i], &w);
25             dist2origin[i] = abs(x[i])+abs(y[i]);
26             total_dist[i] = total_dist[i-1] + abs(x[i]-x[i-1])+abs(y[i]-y[i-1]);
27             total_weight[i] = total_weight[i-1] + w;
28         }
29         front = rear = 1;
30         for(i=1; i<=n; i++){
31             while(front<=rear && total_weight[i]-total_weight[q[front]]>c) front++;
32             d[i]=func(q[front])+total_dist[i]+dist2origin[i];
33             while(front<=rear && func(i)<=func(q[rear])) rear--;
34             q[++rear] = i;
35         }
36         printf("%d\n", d[n]);
37         if(T>0) printf("\n");
38     }
39     return 0;
40 }

今天感觉做题目不很在状态，直接看了训练指南上的分析。。