51Nod 1006 最长公共子序列Lcs

 1 #include <stdio.h>
 2 #define  MAXN  1002
 3 char A[MAXN] = {0};
 4 char B[MAXN] = {0};
 5 char R[MAXN] = {0};
 6 short mat[MAXN][MAXN] = {0};
 7 short max(short a, short b, short c)
 8 {
 9     if(a > b){
10         b = a;
11     }
12     return  b > c ? b : c;
13 }
14 int main()
15 {
16     int  i, j = 0, k;
17     scanf("%s %s", A + 1, B + 1);
18     for(i = 1; A[i]; i++){
19         for(j = 1; B[j]; j++){
20             mat[i][j] = max(mat[i-1][j], mat[i][j-1], mat[i-1][j-1] + (A[i]==B[j] ? 1 : 0));
21         }
22     }
23     i--;
24     j--;
25     k = MAXN - 1;
26     while(i > 0 && j > 0){
27         if(A[i] == B[j]){
28             R[k--] = A[i];
29             i--;
30             j--;
31         }
32         else if(mat[i-1][j] > mat[i][j-1]){
33             i--;
34         }
35         else{
36             j--;
37         }
38     }
39     printf( "%s\n", R + k + 1);
40     return 0;
41 }