调试中遇到的困难主要在于building队列的维护。不能简单地将新增edge加入queue，需要对其方向进行处理。
1 #include <cstdio> 2 #include <algorithm> 3 #include <queue> 4 #include <cstring> 5 6 using namespace std; 7 8 #define N 100 9 10 struct road{ 11 int begin; 12 int end; 13 int value; 14 }; 15 16 bool operator < (road a, road b){ 17 return a.value > b.value; 18 } 19 20 int main(){ 21 int n; 22 while (scanf("%d", &n), n != 0){ 23 int num = n*(n-1)/2; 24 int total_value = 0; 25 int count = 1; 26 road roads[num]; 27 priority_queue<road> roads_building; 28 bool roads_outqueue[num]; 29 bool linked[n]; 30 memset(roads_outqueue, true, sizeof(roads_outqueue)); 31 memset(linked, false, sizeof(linked)); 32 for (int i = 0; i < num; i++){ 33 int built; 34 scanf("%d %d %d %d", &roads[i].begin, &roads[i].end, &roads[i].value, &built); 35 if (built == 1) 36 roads[i].value = 0; 37 } 38 for (int i = 0; i < num; i++) 39 if (roads[i].begin == 1){ 40 roads_building.push(roads[i]); 41 roads_outqueue[i] = false; 42 } 43 linked[0] = true; 44 while (count < n){ 45 road top = roads_building.top(); 46 roads_building.pop(); 47 if (not linked[top.end - 1]){ 48 linked[top.end - 1] = true; 49 total_value += top.value; 50 count += 1; 51 for (int i = 0; i < num; i++) 52 if (roads_outqueue[i]){ 53 if (roads[i].begin == top.end){ 54 roads_building.push(roads[i]); 55 roads_outqueue[i] = false; 56 } 57 else if (roads[i].end == top.end){ 58 road temp; 59 temp.begin = roads[i].end; 60 temp.end = roads[i].begin; 61 temp.value = roads[i].value; 62 roads_building.push(temp); 63 roads_outqueue[i] = false; 64 } 65 } 66 } 67 } 68 printf("%d ", total_value); 69 } 70 return 0; 71 }