WOJ1210-Common Subsequence

A subsequence of a given sequence is the given sequence with some elements (possible none) left out. Given a sequence X = < x1, x2, ..., xm > another sequence Z = < z1, z2, ..., zk > is a subsequence of X if there exists a strictly increasing sequence < i1, i2, ..., ik > of indices of X such that for all j = 1,2,...,k, xij = zj. For example, Z = < a, b, f, c > is a subsequence of X = < a, b, c, f, b, c > with index sequence < 1, 2, 4, 6 >. Given two sequences X and Y the problem is to find the length of the maximum-length common subsequence of X and Y.

输入格式

The program input is from the std input. Each data set in the input contains two strings representing the given sequences. The sequences are separated by any number of white spaces or '\n'. The input data are correct.

输出格式

For each set of data the program prints on the standard output the length of the maximum-length common subsequence from the beginning of a separate line

样例输入

abcfbc         abfcabprogramming    contest abcd           mnp

样例输出

420

#include<stdio.h>#include<string.h>int c[2][10002];char s1[10002],s2[10002];int main() {int i,j;while(scanf("%s %s",&s1,&s2)!=EOF) {int len1 = strlen(s1),len2 =strlen(s2);for (i=0; i<=len1; i++) {c[0][i]=0;c[1][i]=0;}for (i=1; i<=len2; i++) {for (j=1; j<=len1; j++) {if (s2[i-1] == s1[j-1]) c[i%2][j] = c[(i+1)%2][j-1]+1;else c[i%2][j] = c[(i+1)%2][j]>c[i%2][j-1]?c[(i+1)%2][j]:c[i%2][j-1];}}printf("%d\n",c[len2%2][len1]);}return 0;}