POJ2250：Compromise(LCS)

#include <cstdio>
#include <cstring>
#include <string>
#include <vector>
#include <iostream>

using namespace std;

vector<string> str1;
vector<string> str2;
const int maxn = 500+5;
int dp[maxn][maxn];
int road[maxn][maxn];
vector<string> ans;

void LCS() {
    memset(dp, 0, sizeof(dp));

    for(int i = 0; i <= str1.size(); i++) {
        dp[i][0] = 0;
    }

    for(int j = 0; j <= str2.size(); j++) {
        dp[0][j] = 0;
    }

    for(int i = 1; i <= str1.size(); ++i) {
        for(int j = 1; j <= str2.size(); ++j) {
            if(str1[i-1] == str2[j-1]) {//公共字符
                dp[i][j] = dp[i-1][j-1] + 1;
                road[i][j] = 0;
            } else {
                if(dp[i-1][j] > dp[i][j-1]) {//str1的长
                    dp[i][j] = dp[i-1][j];
                    road[i][j] = 1;
                } else {//str2的长
                    dp[i][j] = dp[i][j-1];
                    road[i][j] = -1;
                }
            }
        }
    }
}

void calPath(int n1, int n2) {
    if(n1 == 0 && n2 == 0)
        return;

    if(road[n1][n2] == 0) {
        calPath(n1-1, n2-1);
        ans.push_back(str1[n1-1]);
    }

    if(road[n1][n2] == 1) {
        calPath(n1-1, n2);
    }

    if(road[n1][n2] == -1) {
        calPath(n1, n2-1);
    }

}

int main(void) {
    //freopen("data.in", "r", stdin);
    //ios::sync_with_stdio(false);

    string str;
    while(cin >> str) {
        if(str != "#") {
            str1.push_back(str);

            while(cin >> str && str != "#") {
                str1.push_back(str);
            }
        }

        while(cin >> str && str != "#") {
            str2.push_back(str);
        }

        LCS();
        calPath(str1.size(), str2.size());
        if(ans.size() > 0) {
            for(int i = 0; i < ans.size(); ++i) {
                cout << ans[i];
                if( i != ans.size()-1)
                    cout << " ";
            }
        }
        cout << endl;
    }

    return 0;
}