luogu p1119 灾后重建

luogu p1119 灾后重建
少用memset(),不然吃亏在后边。
在floyd在如果有些点不能走,等价于它们不能作中转点,这样就满足了时效性,也就满足了在变化的图中求任意两点的最短路

 1 #include<iostream>
 2 #include<cstdio>
 3 #include<queue>
 4 #include<algorithm>
 5 #include<cmath>
 6 #include<ctime>
 7 #include<set>
 8 #include<map>
 9 #include<stack>
10 #include<cstring>
11 #define inf 2147483647
12 #define ls rt<<1
13 #define rs rt<<1|1
14 #define lson ls,nl,mid,l,r
15 #define rson rs,mid+1,nr,l,r
16 #define N 100010
17 #define For(i,a,b) for(long long i=a;i<=b;i++)
18 #define p(a) putchar(a)
19 #define g() getchar()
20 
21 using namespace std;
22 
23 long long f[310][310];
24 long long n,m,x,y,c;
25 long long t[500100];
26 long long k,q;
27 
28 void in(long long &x){
29     long long y=1;
30     char c=g();x=0;
31     while(c<'0'||c>'9'){
32         if(c=='-')y=-1;
33         c=g();
34     }
35     while(c<='9'&&c>='0'){
36         x=(x<<1)+(x<<3)+c-'0';c=g();
37     }
38     x*=y;
39 }
40 void o(long long x){
41     if(x<0){
42         p('-');
43         x=-x;
44     }
45     if(x>9)o(x/10);
46     p(x%10+'0');
47 }
48 int main(){
49     in(n);in(m);
50      For(i,0,n)
51          For(j,0,n)
52              f[i][j]=inf;
53          
54      For(i,0,n)
55          t[i]=inf;
56     For(i,0,n-1)
57         in(t[i]);
58     For(i,1,m){
59         in(x);in(y);in(f[x][y]);
60         f[y][x]=f[x][y];
61     }
62     For(i,0,n-1)
63         f[i][i]=0;
64 
65     in(q);
66 
67     For(ii,1,q){
68         in(x);in(y);in(c);
69         while(t[k]<=c){
70             For(i,0,n-1)
71                 For(j,0,n-1)
72                     f[i][j]=min(f[i][j],f[i][k]+f[k][j]);
73             k++;
74         }
75         if(f[x][y]==inf||t[x]>c||t[y]>c)
76             o(-1);
77         else
78             o(f[x][y]);
79         p('\n');
80     }
81     return 0;
82 }
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posted @ 2019-01-26 10:32  WeiAR  阅读(103)  评论(0编辑  收藏  举报