[問題] Connected Component Label使用BFS

看板C_and_CPP (C/C++)作者MaconChou (得罪了方丈還想走)時間15年前 (2010/10/03 00:45)推噓2(2推 0噓 5→)

留言7則, 3人參與討論串1/1

遇到的問題： (題意請描述清楚) 1. free()了front以及rear所指向的位址為何只有front呈現NULL!? 2. 在do while時,malloc()會產生尚未free()的位址!? 希望得到的正確結果： 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 1 1 0 0 0 1 1 1 1 1 1 1 0 0 0 0 0 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2 2 2 2 2 0 0 0 0 0 2 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 程式跑出來的錯誤結果： Candidate 1 add() new_data: 3e2430 front: 0 rear: 0 front: 3e2430 rear: 3e2430 do while get() *i: 0 *j: 0 *flag: 3e2430 rear: 3e2430 *i: 1 *j: 1 *flag: 0 rear: 3e2430 add() new_data: 3e2448 front: 0 rear: 3e2430 front: 3e2448 rear: 3e2448 add() new_data: 3e2460 front: 3e2448 rear: 3e2448 front: 3e2448 rear: 3e2460 add() new_data: 3e2478 front: 3e2448 rear: 3e2460 front: 3e2448 rear: 3e2478 do while get() *i: 1 *j: 1 *flag: 3e2448 rear: 3e2478 *i: 1 *j: 2 *flag: 3e2460 rear: 3e2478 add() new_data: 3e2460 front: 3e2460 rear: 3e2478 front: 3e2460 rear: 3e2460 add() new_data: 3e2490 front: 3e2460 rear: 3e2460 front: 3e2460 rear: 3e2490 do while get() *i: 1 *j: 2 *flag: 3e2460 rear: 3e2490 *i: 1 *j: 3 *flag: 3e2490 rear: 3e2490 add() new_data: 3e2490 front: 3e2490 rear: 3e2490 front: 3e2490 rear: 3e2490 add() new_data: 3e24a8 front: 3e2490 rear: 3e2490 front: 3e2490 rear: 3e24a8 ....... ...... ..... .... ... .. . 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 2 2 2 2 2 2 2 0 0 0 2 2 2 2 2 2 2 0 0 0 0 0 3 3 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4 4 4 4 4 0 0 0 0 0 4 4 4 4 4 0 0 0 0 0 0 0 0 0 0 0 0 開發平台： (例: VC++ or gcc/g++ or Dev-C++, Windows or Linux) DEV-C++ 4.9.9.2 Windows XP 有問題的code： (請善用置底文標色功能) #include <stdio.h> #include <stdlib.h> typedef struct queue{ int offset_i, offset_j; struct queue *next; }queue; queue *front = NULL, *rear = NULL; void add(int [][10], int, int, int); void get(int*, int*); int main() { int i, j, x = 0; int n = 0, m = 0, flag = 0; int block = 1; int arry[10][10] = {{0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 5, 5, 5, 5, 5, 0, 0, 0, 0}, {0, 5, 5, 5, 5, 5, 0, 0, 0, 0}, {0, 5, 5, 5, 5, 5, 5, 5, 0, 0}, {0, 5, 5, 5, 5, 5, 5, 5, 0, 0}, {0, 0, 0, 5, 5, 5, 0, 0, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, {0, 0, 0, 5, 5, 5, 5, 5, 0, 0}, {0, 0, 0, 5, 5, 5, 5, 5, 0, 0}, {0, 0, 0, 0, 0, 0, 0, 0, 0, 0}}; for(i = 0; i <= 9; i++) for(j = 0 ; j <= 9; j++){ if(5 == arry[i][j]){ printf("\nCandidate %d\n", block); add(arry, block, i, j); do{ puts("do while"); get(&n ,&m); // system("PAUSE"); if(5 == arry[n - 1][m - 1]) add(arry, block, n - 1, m - 1); if(5 == arry[n - 1][m]) add(arry, block, n - 1, m); if(5 == arry[n - 1][m + 1]) add(arry, block, n - 1, m + 1); if(5 == arry[n][m - 1]) add(arry, block, n, m - 1); if(5 == arry[n][m + 1]) add(arry, block, n, m + 1); if(5 == arry[n + 1][m - 1]) add(arry, block, n + 1, m - 1); if(5 == arry[n + 1][m]) add(arry, block, n + 1, m); if(5 == arry[n + 1][m + 1]) add(arry, block, n + 1, m + 1); }while(front != NULL); block++; } } for(i = 0; i <= 9; i++) for(j = 0 ; j <= 9; j++){ x++; printf("%d\t", arry[i][j]); if(10 == x){ puts(""); x = 0; } } system("PAUSE"); return 0; } void add(int temp[][10], int block, int i, int j) { queue *new_data; new_data = (queue*)malloc(sizeof(queue)); puts("add()"); printf("new_data: %x\tfront: %x\trear: %x\n",new_data, front, rear); temp[i][j] = block; new_data -> offset_i = i; new_data -> offset_j = j; if(front == NULL) front = new_data; else rear -> next = new_data; rear = new_data; new_data -> next = NULL; printf("front: %x\trear: %x\n", front, rear); return; } void get(int *i, int *j) { queue *free_data; puts("get()"); printf("*i: %d *j: %d *flag: %x rear: %x\n", *i, *j, front, rear); if(front == NULL) return; else{ *i = front -> offset_i; *j = front -> offset_j; front = front -> next; free_data = front; free(free_data); printf("*i: %d *j: %d *flag: %x rear: %x\n", *i, *j, front, rear); } return; } 補充說明：想了好久,也debug好久還是不知所云. 所以上來請教各位版上的先進, 小弟哪邊寫不好還是觀念不正確或是... 謝謝!!! -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 61.64.210.117 ※ 編輯: MaconChou 來自: 61.64.210.117 (10/03 00:48) ※ 編輯: MaconChou 來自: 61.64.210.117 (10/03 00:50)