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一道bfs的题目,不敢说水..好吧,这题的确是入门题....
因为自己做了快2小时..
还是因为思维考虑的不全面的缘故;
一开始把加减的情况都写在了一个循环里...交了一遍,WA..
检查了挺久才检查出来的....把过程打印出来也有不靠谱的地方...
后来分析了一下逻辑...发现之前的修改会影响到后面对数字的修改;其实就是我做了2次修改,才记录了一次;
而且这种做法还会使压入队列的情况减少...
后来修改的时候吧加法改少了一部分...又花了一点时间debug..
不过怎么说..最后还是做出来了...
1 #include <iostream> 2 #include <queue> 3 #include <string.h> 4 #include <algorithm> 5 using namespace std; 6 #define maxn 10005 7 struct node{ 8 int count; 9 int a[4]; 10 }; 11 bool visit[maxn]; 12 int N; 13 int begin_value,end_value; 14 int getValue(int *a) 15 { 16 int result = 0; 17 for (int i = 0; i < 4; i++){ 18 result = result * 10 + a[i]; 19 } 20 return result; 21 } 22 int bfs() 23 { 24 queue<node> game; 25 node cur, next; 26 cur.count = 0; 27 cur.a[0] = begin_value / 1000; 28 cur.a[1] = (begin_value % 1000) / 100; 29 cur.a[2] = (begin_value % 100) / 10; 30 cur.a[3] = begin_value % 10; 31 game.push(cur); 32 visit[getValue(cur.a)] = true; 33 while (!game.empty()){ 34 cur = game.front(); 35 game.pop(); 36 int value = getValue(cur.a); 37 //printf("%d %d\n", value,cur.count); 38 if (value == end_value){ 39 return cur.count; 40 } 41 //减法: 42 for (int i = 0; i < 4; i++){ 43 next = cur; 44 if (cur.a[i] == 1){ 45 next.a[i] = 9; 46 if (!visit[getValue(next.a)]) 47 { 48 next.count = cur.count + 1; 49 visit[getValue(next.a)] = true; 50 game.push(next); 51 } 52 } 53 else{ 54 next.a[i] = cur.a[i] - 1; 55 if (!visit[getValue(next.a)]) 56 { 57 next.count = cur.count + 1; 58 visit[getValue(next.a)] = true; 59 game.push(next); 60 } 61 62 } 63 } 64 //加法 65 for (int i = 0; i < 4; i++){ 66 next = cur; 67 if (cur.a[i] == 9){ 68 next.a[i] = 1; 69 if (!visit[getValue(next.a)]) 70 { 71 next.count = cur.count + 1; 72 visit[getValue(next.a)] = true; 73 game.push(next); 74 } 75 } 76 else{ 77 next.a[i] = cur.a[i] + 1; 78 if (!visit[getValue(next.a)]) 79 { 80 next.count = cur.count + 1; 81 visit[getValue(next.a)] = true; 82 game.push(next); 83 } 84 } 85 } 86 for (int i = 0; i < 3; i++) 87 { 88 next = cur; 89 swap(next.a[i], next.a[i + 1]); 90 if (!visit[getValue(next.a)]) 91 { 92 next.count = cur.count + 1; 93 visit[getValue(next.a)] = true; 94 game.push(next); 95 96 } 97 } 98 } 99 return 0; 100 } 101 102 int main() 103 { 104 while (~scanf("%d", &N)){ 105 while (N--){ 106 scanf("%d %d", &begin_value, &end_value); 107 memset(visit, false, sizeof(visit)); 108 printf("%d\n", bfs()); 109 } 110 } 111 return 0; 112 }
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原文地址:http://www.cnblogs.com/xiaoniuniu/p/4483723.html