[HDOJ1022]Train Problem I

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1022

手写栈，模拟出入的过程。很简单，不停入栈，如果和当前要求出站车辆相同的话就出站，否则继续入栈。

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
#include <iostream>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <stack>
#include <list>
#include <vector>

using namespace std;

const int maxn = 100010;
int n;
char in[maxn];
char out[maxn];
char mystack[maxn];
int ans[maxn];  //记下步骤
int top, head, stp, now;

void init() {
    memset(mystack, 0, sizeof(mystack));
    memset(ans, 0, sizeof(ans));
    stp = 0;    //步骤
    top = 0;    //栈顶
    head = 0;   //车头
    now = 0;    //待出栈车辆
}

void solve() {
    while(head < n) {
            mystack[++top] = in[head++];
            ans[stp++] = 1;
            while(top && mystack[top] == out[now]) {
                top--;
                now++;
                ans[stp++] = 0;
            }
    }
    if(now == n) {
        printf("Yes.
");
        for(int i = 0; i < stp; i++) {
            if(ans[i]) {
                printf("in
");
            }
            else {
                printf("out
");
            }
        }
        printf("FINISH
");
    }
    else {
        printf("No.
FINISH
");
    }
}
int main() {
    // freopen("in", "r", stdin);
    while(~scanf("%d", &n)) {
        scanf("%s %s", in, out);
        init();
        solve();
    }
}