LCS记录路径

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <iomanip>
 4 #include <cstring>
 5 #include <climits>
 6 #include <complex>
 7 #include <fstream>
 8 #include <cassert>
 9 #include <cstdio>
10 #include <bitset>
11 #include <vector>
12 #include <deque>
13 #include <queue>
14 #include <stack>
15 #include <ctime>
16 #include <set>
17 #include <map>
18 #include <cmath>
19 
20 using namespace std;
21 
22 const int mod = 100007;
23 const int maxn = 1010;
24 char a[maxn];
25 char b[maxn];
26 int dp[maxn][maxn];
27 int fa[mod];
28 int na, nb;
29 
30 int main() {
31     // freopen("in", "r", stdin);
32     while(~scanf("%s %s", a, b)) {
33         memset(dp, 0, sizeof(dp));
34         memset(fa, -1, sizeof(fa));
35         na = strlen(a);
36         nb = strlen(b);
37         for(int i = 0; i < na; i++) {
38             for(int j = 0; j < nb; j++) {
39                 if(a[i] == b[j]) {
40                     if(dp[i][j] + 1 > max(dp[i][j+1], dp[i+1][j])) {
41                         dp[i+1][j+1] = dp[i][j] + 1;
42                         // int cur = (((i + 1) * 59) % mod + ((j + 1) * 61) % mod) % mod;
43                         // int pre = ((i * 59) % mod + (j * 61) % mod) % mod;
44                         // fa[cur][0] = pre;
45                         // fa[cur][1] = i;
46                         // ii = cur;
47                     }
48                     else dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
49                 }
50                 else {
51                     dp[i+1][j+1] = max(dp[i][j+1], dp[i+1][j]);
52                 }
53             }
54         }
55         int ii = na;
56         int jj = nb;
57         char st[maxn];
58         int top = 0;
59         while(dp[ii][jj]) {
60             if(dp[ii][jj] == dp[ii-1][jj]) ii--;
61             else if(dp[ii][jj] == dp[ii][jj-1]) jj--;
62             else {
63                 ii--, jj--;
64                 st[top++] = a[ii];
65             }
66 
67         }
68         while(top) printf("%c", st[--top]);
69         printf("\n");
70     }
71     return 0;
72 }