Zipper

Zipper Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 8072    Accepted Submission(s): 2843 Problem Description Given three strings, you are to determine whether the third string can be formed by combining the characters in the first two strings. The first two strings can be mixed arbitrarily, but each must stay in its original order. For example, consider forming "tcraete" from "cat" and "tree": String A: cat String B: tree String C: tcraete As you can see, we can form the third string by alternating characters from the two strings. As a second example, consider forming "catrtee" from "cat" and "tree": String A: cat String B: tree String C: catrtee Finally, notice that it is impossible to form "cttaree" from "cat" and "tree". Input The first line of input contains a single positive integer from 1 through 1000. It represents the number of data sets to follow. The processing for each data set is identical. The data sets appear on the following lines, one data set per line. For each data set, the line of input consists of three strings, separated by a single space. All strings are composed of upper and lower case letters only. The length of the third string is always the sum of the lengths of the first two strings. The first two strings will have lengths between 1 and 200 characters, inclusive. Output For each data set, print: Data set n: yes if the third string can be formed from the first two, or Data set n: no if it cannot. Of course n should be replaced by the data set number. See the sample output below for an example. Sample Input 3 cat tree tcraete cat tree catrtee cat tree cttaree Sample Output Data set 1: yes Data set 2: yes Data set 3: no

注意一定要判最后一个字母可以匹配，要不超时。。。

代码：

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
int n;
bool ans;
int len1, len2, len3;
char s1[], s2[], s3[];
void get(int &x){
    scanf("%d", &x);
}
void get(char *s){
    scanf("%s", s);
}
void work(int i, int j, int k);
int main(){

    int kase = ;
    get(n);
    while(n-- > ){
        get(s1);
        get(s2);
        get(s3);
        ans = false;

        len1 = strlen(s1);
        len2 = strlen(s2);
        len3 = strlen(s3);
        if(len1 + len2 == len3 && (s1[len1-]==s3[len3-]||s2[len2-]==s3[len3-])){
            work(, , );
        }
        if(ans){

            printf("Data set %d: yes\n", kase++);
        }else{
            printf("Data set %d: no\n", kase++);
        }
    }
    return ;
}

void work(int i, int j, int k) {

    if(ans)
        return;
    if(k >= len3){
        ans = true;
        return;
    }

    if(i < len1 && s1[i] == s3[k]){
        work(i + , j, k + );
    }
    if(j < len2 && s2[j] == s3[k]){
        work(i, j + , k + );
    }
}

java:

package com.hbc.week3;

import java.util.Scanner;

public class Zipper {
    private static int n;
    private static Scanner cin = new Scanner(System.in);
    private static boolean ans;
    public static void main(String[] args) {
        String s1, s2, s3;
        int kase = 1;
        n = cin.nextInt();
        while(n-- > 0){
            s1 = cin.next();
            s2 = cin.next();
            s3 = cin.next();
            ans = false;
            if(s1.length() + s2.length() == s3.length() && (s1.charAt(s1.length() - 1)==s3.charAt(s3.length() - 1)
                    ||s2.charAt(s2.length() - 1) == s3.charAt(s3.length() - 1))){
                work(s1, s2, s3, 0, 0, 0);
            }

            if(ans){

                System.out.println("Data set " + (kase++) + ": yes");
            }else{
                System.out.println("Data set " + (kase++) + ": no");
            }
        }
    }
    private static void work(String s1, String s2, String s3, int i, int j, int k) {

        if(k >= s3.length()){
            ans = true;
            return;
        }

        if(i < s1.length() && s1.charAt(i) == s3.charAt(k)){
            work(s1, s2, s3, i + 1, j, k + 1);
        }
        if(j < s2.length() && s2.charAt(j) == s3.charAt(k)){
            work(s1, s2, s3, i, j + 1, k + 1);
        }
    }
}