【codeforces 765B】Code obfuscation

【题目链接】:http://codeforces.com/contest/765/problem/B

【题意】

让你把每个变量都依次替换成a,b,c,….d这些字母;
且要按顺序先用a再用b….c.d.e….z

【题解】

模拟一下这个过程就好了;
每次看看最左边那个字母是什么(当然之前已经模拟过的除外);
看看是不是当前枚举到的字母;
不是的话就错误;

【完整代码】

#include <bits/stdc++.h>using namespace std;#define lson l,m,rt<<1#define rson m+1,r,rt<<1|1#define LL long long#define rep1(i,a,b) for (int i = a;i <= b;i++)#define rep2(i,a,b) for (int i = a;i >= b;i--)#define mp make_pair#define pb push_back#define fi first#define se second#define rei(x) scanf("%d",&x)#define rel(x) scanf("%I64d",&x)typedef pair<int,int> pii;typedef pair<LL,LL> pll;const int dx[9] = {0,1,-1,0,0,-1,-1,1,1};const int dy[9] = {0,0,0,-1,1,-1,1,-1,1};const double pi = acos(-1.0);const int N = 500+100;char s[N];bool bo[N];int len;int main(){    //freopen("F:\\rush.txt","r",stdin);    scanf("%s",s+1);    len = strlen(s+1);    for (char now = 'a';now <= 'z' ;now++)    {        int j = -1;        rep1(i,1,len)            if (!bo[i])                {                    j = i;                    break;                }        if (j==-1)            return puts("YES"),0;        if (s[j]!=now)            return puts("NO"),0;        rep1(i,1,len)            if (s[i]==now)                bo[i] = true;    }    puts("YES");    return 0;}