1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 | #include <stdio.h> #include <algorithm> using namespace std; int arr[500][500] = { 0 }; int maxLen = 0, n; //way=1(동), way=-1(서),way=-2(북), way=2(남) void dfs(int y, int x, int len, int way) { if (way == 2) {//남 if (arr[y + 1][x] == 0) { arr[y + 1][x] = 2; dfs(y + 1, x, len + 1, 2); arr[y + 1][x] = 0; }//장애물을 만났을때 int flag = 0; if (arr[y + 1][x] == 1) { if (arr[y][x + 1] == 0) { arr[y][x + 1] = 2; dfs(y, x + 1, len + 1, 1); arr[y][x + 1] = 0; flag++; } if (arr[y][x - 1] == 0) { arr[y][x - 1] = 2; dfs(y, x - 1, len + 1, -1); arr[y][x - 1] = 0; flag++; } } if (arr[y + 1][x] == 2 || flag==0) { maxLen = max(maxLen, len); return; } } if (way == -2) {//북 if (arr[y - 1][x] == 0) { arr[y - 1][x] = 2; dfs(y - 1, x, len + 1, -2); arr[y - 1][x] = 0; }//장애물을 만났을때 int flag = 0; if (arr[y - 1][x] == 1) { if (arr[y][x + 1] == 0) { arr[y][x + 1] = 2; dfs(y, x + 1, len + 1, 1); arr[y][x + 1] = 0; flag++; } if (arr[y][x - 1] == 0) { arr[y][x - 1] = 2; dfs(y, x - 1, len + 1, -1); arr[y][x - 1] = 0; flag++; } } if (arr[y - 1][x] == 2 || flag == 0) { maxLen = max(maxLen, len); return; } } if (way == 1) {//동 if (arr[y][x + 1] == 0) { arr[y][x + 1] = 2; dfs(y, x + 1, len + 1, 1); arr[y][x + 1] = 0; }//장애물을 만났을때 int flag = 0; if (arr[y][x + 1] == 1) { if (arr[y - 1][x] == 0) { arr[y - 1][x] = 2; dfs(y - 1, x, len + 1, -2); arr[y - 1][x] = 0; flag++; } if (arr[y + 1][x] == 0) { arr[y + 1][x] = 2; dfs(y + 1, x, len + 1, 2); arr[y + 1][x] = 0; flag++; } } if (arr[y][x + 1] == 2 || flag == 0) { maxLen = max(maxLen, len); return; } } if (way == -1) {//서 if (arr[y][x - 1] == 0) { arr[y][x - 1] = 2; dfs(y, x - 1, len + 1, -1); arr[y][x - 1] = 0; }//장애물을 만났을때 int flag = 0; if (arr[y][x - 1] == 1) { if (arr[y - 1][x] == 0) { arr[y - 1][x] = 2; dfs(y - 1, x, len + 1, -2); arr[y - 1][x] = 0; flag++; } if (arr[y + 1][x] == 0) { arr[y + 1][x] = 2; dfs(y + 1, x, len + 1, 2); arr[y + 1][x] = 0; flag++; } } if (arr[y][x - 1] == 2 || flag == 0) { maxLen = max(maxLen, len); return; } } return; } int main() { int b; scanf("%d %d", &n, &b); getchar(); for (int i = 0; i <= n + 1; i++) { arr[0][i] = 1; arr[i][0] = 1; arr[n + 1][i] = 1; arr[i][n + 1] = 1; } for (int i = 0; i < b; i++) { char alpha; int y; scanf("%c%d", &alpha, &y); getchar(); int x = (int)(alpha - 'A' + 1); arr[y][x] = 1; } arr[1][1] = 2; dfs(1, 1, 1, 1); dfs(1, 1, 1, 2); printf("%d", maxLen); } | cs |
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