hd 1981 A Special Text Editor

看似很简单的题目,第一感觉就是直接模拟了,结果TLE...然后套论坛上是look一下后,改进了一下,结果还是TLE,无奈下只好购买代码了,不过理解了就好,呵呵.直接j的顺序是从后往前

#include <iostream>
#include <string.h>
using namespace std;
typedef struct
...{
    char c;
    int s, e;
}Op;
char s[80002];
Op p[3001];
int n, nn;
int main()
...{
    int T, i, j, k;
    char c;
    int m;
    int a, b;
    scanf("%d",&T);
    while (T--)
    ...{
        scanf("%d%d",&n,&m);
        scanf("%s",s);
        nn = 0;
        for (i=0; i<m; ++i)
        ...{
            getchar();
            scanf("%c",&c);
            if(c == 'Q')
            ...{
                scanf("%d",&a);
                --a;
                int cnt = 0;
                for (j=nn-1; j>=0; --j)
                ...{
                    if(a<p[j].s || a>p[j].e)
                        continue;
                    if(p[j].c == 'R')
                    ...{
                        a = p[j].s+p[j].e-a;
                    }
                    else if(p[j].c == 'S' )
                    ...{
                        ++cnt;
                    }
                }
                c = s[a];
                for (j=0; j<cnt; j++)
                ...{
                    if(c-'z' == 0)
                        c = 'a';
                    else
                        ++c;
                }
                printf("%c ", c);
            }
            else
            ...{
                scanf("%d%d",&a,&b);
                p[nn].c = c, p[nn].s = a-1, p[nn++].e = b-1;
            }
        }
    }
    return 0;
}