You are given a non-empty string s consisting of lowercase English letters. You have to pick exactly one non-empty substring of s and shift all its letters 'z' 'y' 'x' 'b' 'a' 'z'. In other words, each character is replaced with the previous character of English alphabet and 'a' is replaced with 'z'.
What is the lexicographically minimum string that can be obtained from s by performing this shift exactly once?
The only line of the input contains the string s (1 ≤ |s| ≤ 100 000) consisting of lowercase English letters.
Print the lexicographically minimum string that can be obtained from s by shifting letters of exactly one non-empty substring.
codeforces
bncdenqbdr
abacaba
aaacaba
String s is lexicographically smaller than some other string t of the same length if there exists some 1 ≤ i ≤ |s|, such that s1 = t1, s2 = t2, ..., si - 1 = ti - 1, and si < ti.
题目连接:http://codeforces.com/contest/709/problem/C
题意:将s的子串进行一次变换,输出字典序最小的s。
思路:水题。注意一定要进行一次变换。
代码:
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 using namespace std; 5 string s; 6 char ans[100100]; 7 int main() 8 { 9 int i; 10 cin>>s; 11 char ch; 12 int sign=0,flag=0; 13 for(i=0; i<s.size(); i++) 14 { 15 if(s[i]-1>='a') ch=s[i]-1; 16 else ch='z'; 17 if(sign==0&&ch<=s[i]) ans[i]=ch,flag=1; 18 else if(flag==0) ans[i]=s[i]; 19 else ans[i]=s[i],sign=1; 20 } 21 if(flag==0) ans[i-1]=ch; 22 for(i=0; i<s.size(); i++) 23 printf("%c",ans[i]); 24 cout<<endl; 25 return 0; 26 }