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CodeForces 709C Letters Cyclic Shift (水题)

题意:给定一个字符串,让你把它的一个子串字符都减1,使得总字符串字典序最小。

析:由于这个题是必须要有一个字串,所以你就要注意这个只有一个字符a的情况,其他的就从开始减 1,如果碰到a了就不减了,如果到最后一位了还没开始减,

就减最后一位。

代码如下:

#pragma comment(linker, "/STACK:1024000000,1024000000")#include <cstdio>#include <string>#include <cstdlib>#include <cmath>#include <iostream>#include <cstring>#include <set>#include <queue>#include <algorithm>#include <vector>#include <map>#include <cctype>#include <cmath>#include <stack>#define freopenr freopen("in.txt", "r", stdin)#define freopenw freopen("out.txt", "w", stdout)using namespace std;typedef long long LL;typedef pair<int, int> P;const int INF = 0x3f3f3f3f;const double inf = 0x3f3f3f3f3f3f;const double PI = acos(-1.0);const double eps = 1e-8;const int maxn = 1e5 + 5;const int mod = 1e8;const char *mark = "+-*";const int dr[] = {-1, 0, 1, 0, 1, 1, -1, -1};const int dc[] = {0, 1, 0, -1, -1, 1, 1, -1};int n, m;const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};inline int Min(int a, int b){ return a < b ? a : b; }inline int Max(int a, int b){ return a > b ? a : b; }inline LL Min(LL a, LL b){ return a < b ? a : b; }inline LL Max(LL a, LL b){ return a > b ? a : b; }inline bool is_in(int r, int c){    return r >= 0 && r < n && c >= 0 && c < m;}char s[maxn];int main(){    while(scanf("%s", s) == 1){        int len = strlen(s);        int ok = false;        for(int i = 0; i < len; ++i){            if(s[i] ==‘a‘ && ok)  break;            if(i == len-1 && !ok){                s[i] = (s[i]-‘a‘+25) % 26 + ‘a‘;                break;            }            if(s[i] != ‘a‘){                ok = true;                --s[i];            }        }        printf("%s\n", s);    }    return 0;}

 

CodeForces 709C Letters Cyclic Shift (水题)