2019 ICPC 银川网络赛 F-Moving On (卡Cache)

Firdaws and Fatinah are living in a country with nn cities, numbered from 11 to nn. Each city has a risk of kidnapping or robbery.

Firdaws's home locates in the city uu, and Fatinah's home locates in the city vv. Now you are asked to find the shortest path from the city uu to the city vv that does not pass through any other city with the risk of kidnapping or robbery higher than ww, a threshold given by Firdaws.

Input

The input contains several test cases, and the first line is a positive integer TT indicating the number of test cases which is up to 5050.

For each test case, the first line contains two integers n (1 le n le 200)n(1≤n≤200) which is the number of cities, and q (1 le q le 2 imes 10^4)q(1≤q≤2×104) which is the number of queries that will be given. The second line contains nn integers r_1, r_2, cdots , r_nr1​,r2​,⋯,rn​ indicating the risk of kidnapping or robbery in the city 11 to nn respectively. Each of the following nn lines contains nn integers, the jj-th one in the ii-th line of which, denoted by d_{i,j}di,j​, is the distance from the city iito the city jj.

Each of the following qq lines gives an independent query with three integers u,vu,v and ww, which are described as above.

We guarantee that 1 le r_i le 10^5, 1 le d_{i,j} le 10^5 (i eq j), d_{i,i} = 01≤ri​≤105,1≤di,j​≤105(i�​=j),di,i​=0 and d_{i,j} = d_{j,i}di,j​=dj,i​. Besides, each query satisfies 1 le u,v le n1≤u,v≤n and 1 le w le 10^51≤w≤105.

Output

For each test case, output a line containing Case #x: at first, where xx is the test case number starting from 11. Each of the following qq lines contains an integer indicating the length of the shortest path of the corresponding query.

输出时每行末尾的多余空格,不影响答案正确性

样例输入复制

1
3 6
1 2 3
0 1 3
1 0 1
3 1 0
1 1 1
1 2 1
1 3 1
1 1 2
1 2 2
1 3 2

样例输出复制

Case #1:
0
1
3
0
1
2

这个题,比较简单的最短路,将城市按照犯罪率从低到高排序,松弛操作从最低的开始松弛,在通过一纬保存犯罪率的下标,这样的话就是3纬Floyd,但是这个题,太变态了,卡cache,第三维访问速度慢,就是靠近数组首地址的位置访问速度快,因为第三维访问的最多,所以这个题不把第三维放到第一维,优化了极限的速是3001MS超了1毫秒,很难受,别的队伍告诉我们要换一下维数,一开始不知道为什么,问他们也不知道,知道查了题解才知道,这个叫cache,等着学操作系统在深入,现在先知道访问最多的放前面,而且这个时间优化有多恐怖,1280ms过了,就简单换了个位置,长见识了以后记住了。

#include<iostream>
#include<queue>
#include<algorithm>
#include<set>
#include<cmath>
#include<vector>
#include<map>
#include<stack>
#include<bitset>
#include<cstdio>
#include<cstring>
//---------------------------------Sexy operation--------------------------//

#define cini(n) scanf("%d",&n)
#define cinl(n) scanf("%lld",&n)
#define cinc(n) scanf("%c",&n)
#define cins(s) scanf("%s",s)
#define coui(n) printf("%d",n)
#define couc(n) printf("%c",n)
#define coul(n) printf("%lld",n)
//___________________________Dividing Line__________________________________/
using namespace std;
int n, m, T, q,i,j,k,ans,u,v,w;
int ma[300][300][300];
int wx[300];
int sx[300];
inline bool cmp( int x,int y )
{
    return wx[x]<wx[y];
}
int main()
{
    int cnt = 0;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d %d",&n,&q);
        for(i = 1; i <= n; i++)
        {
            sx[i] = i;
            scanf("%d",&wx[i]);
        }
        sort(sx+1, sx+1+n, cmp);
        for( i = 1; i <= n; i++)
        {
            for(j = 1; j <= n; j++)
            {
                scanf("%d",&ma[0][i][j]);
            }
        }
            for(k = 1; k <= n; k++)
            {
                for(i = 1; i <= n; i++)
                {
                    for(j = 1; j <= n; j++)
                    {
                        ma[k][i][j] = min(ma[k-1][i][j], ma[k-1][i][sx[k]]+ma[k-1][sx[k]][j]);
                    }
                }
            }
        printf("Case #%d:
",++cnt);
        while(q--)
        {
            scanf("%d%d%d",&u,&v,&w);
            ans = 0;
            for(i = n; i >= 1; i--)
            {
                if(wx[sx[i]]<=w)
                {
                    ans = i;
                    break;
                }
            }
            printf("%d
",ma[ans][u][v]);
        }
    }
    return 0;
}
原文地址:https://www.cnblogs.com/lunatic-talent/p/12798759.html