【题解】NOIP2017时间复杂度

　　对大模拟抱有深深的恐惧……不过这次写好像还好？拿个栈维护一下循环的嵌套，然后重定义一下读入即可。记得去年在考场上面死活调不粗来，代码也奇丑无比……希望今年能好一点吧！

#include <bits/stdc++.h>

using namespace std;

#define maxn 100000

int L, mark[maxn];

char ans[maxn];

int fread(int t)

{

    int x = , k = ;

    char c; c = ans[t]; t ++;

    while(t < strlen(ans) && (c < '' || c > ''))

    {

        if(c == '-') k = -;

        if(c == 'n') x = ;

        c = ans[t]; t ++;

    }

    while(t < strlen(ans) && c >= '' && c <= '')

        x = x *  + c - '', c = ans[t], t ++;

    return x * k;

}

int read()

{

    int x = , k = ;

    char c; c = getchar();

    while(c < '' || c > '')

    {

        if(c == '-') k = -;

        if(c == 'n') { x = ; return x; }

        c = getchar();

    }

    while(c >= '' && c <= '') x = x *  + c - '', c = getchar();

    return x * k;

}

struct node

{

    char c; int num;

    node(char _c = 'z' + , int _num = )

    { c = _c, num = _num; }

}S[maxn];

void Work()

{

    memset(mark, , sizeof(mark));

    int cal = , top = , cnt = , err = , flag = ;

    for(int i = ; i <= L; i ++)

    {

        char c; cin >> c;

        if(c == 'F')

        {

            char x; cin >> x;

            if(mark[x - 'a']) flag = ;

            int l = read(), r = read();

            mark[x - 'a'] = ;

            if(r - l >  && !err) cnt ++, cal = max(cal, cnt);

            if(l > r) err ++;

            S[++ top] = node(x, r - l);

        }

        else

        {

            if(!top) { flag = ; continue; }

            mark[S[top].c - 'a'] = ;

            if(!err) cnt -= S[top].num > ;

            if(S[top].num < ) err --;

            top --;

        }

    }

    int len = strlen(ans), tag = , t = ;

    for(int i = ; i < len; i ++)

        if(ans[i] == 'n') tag = i + ;

        else if(tag && i == tag) { t = fread(i); break; }

    if(top) flag = ;

    if(flag) { printf("ERR\n"); return; }

    if(cal != t) flag = ;

    if(flag) { printf("No\n"); return; }

    printf("Yes\n"); return;

}

int main()

{

    int T; scanf("%d", &T);

    while(T --)

    {

        scanf("%d %s", &L, ans);

        Work();

    }

    return ;

}