二分+Dijkstra。
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <algorithm> 5 #include <queue> 6 using namespace std; 7 8 #define MAXN 105 9 #define INF 1000001 10 11 int n, m; 12 int map[MAXN][MAXN], al[MAXN], bk[MAXN], path[MAXN]; 13 bool visit[MAXN]; 14 int low, high; 15 int ans, dif; 16 17 int dijkstra() { 18 int i, j, v, min; 19 20 if (al[1]<low || al[1]>high) 21 return INF; 22 23 memset(visit, false, sizeof(visit)); 24 visit[1] = true; 25 for (i=1; i<=n; ++i) { 26 if (al[i]>=low && al[i]<=high) 27 path[i] = map[1][i]; 28 else 29 path[i] = INF; 30 } 31 32 for (i=1; i<n; ++i) { 33 min = INF; 34 for (j=1; j<=n; ++j) { 35 if (!visit[j] && path[j]<min) { 36 v = j; 37 min = path[j]; 38 } 39 } 40 if (min == INF) 41 break; 42 visit[v] = true; 43 for (j=1; j<=n; ++j) { 44 if (!visit[j] && map[v][j]+min<path[j] && al[j]>=low && al[j]<=high) 45 path[j] = map[v][j] + min; 46 } 47 } 48 return path[n]; 49 } 50 51 int main() { 52 int t, min, l, r, max, mid; 53 int i, j, k, tmp; 54 55 scanf("%d", &t); 56 while (t--) { 57 scanf("%d %d", &n, &m); 58 min = dif = 1000000001; 59 ans = INF; 60 max = 0; 61 for (i=1; i<=n; ++i) { 62 scanf("%d", &al[i]); 63 if (al[i] < min) min = al[i]; 64 if (al[i] > max) max = al[i]; 65 bk[i] = al[i]; 66 } 67 for (i=1; i<=n; ++i) { 68 map[i][i] = 0; 69 for (j=i+1; j<=n; ++j) 70 map[i][j] = map[j][i] = INF; 71 } 72 while (m--) { 73 scanf("%d %d %d", &i, &j, &k); 74 if (map[i][j] > k) 75 map[i][j] = map[j][i] = k; 76 } 77 sort(bk+1, bk+1+n); 78 l = 0; r = max-min+1; 79 while (l < r) { 80 mid = (l + r)>>1; 81 bool flag = false; 82 for (i=1; i<=n; ++i) { 83 low = bk[i]; 84 high = bk[i] + mid; 85 tmp = dijkstra(); 86 if (tmp != INF) { 87 flag = true; 88 break; 89 } 90 } 91 if ( flag ) { 92 if (mid < dif) { 93 dif = mid; 94 ans = tmp; 95 } else if (mid==dif && ans > tmp) { 96 ans = tmp; 97 } 98 r = mid; 99 } else { 100 l = mid + 1; 101 } 102 } 103 printf("%d %d ", dif, ans); 104 } 105 106 return 0; 107 }