B. Pasha and String
time limit per test
memory limit per test
input
output
s for his birthday, the string consists of lowercase Latin letters. The letters in the string are numbered from 1 to |s| from left to right, where |s|
m days performing the following transformations on his string — each day he chose integer ai and reversed a piece of string (a segment) from position ai to position|s| - ai. It is guaranteed that 2·ai ≤ |s|.
m
Input
s of length from 2 to 2·105
m (1 ≤ m ≤ 105) — the number of days when Pasha changed his string.
m space-separated elements ai (1 ≤ ai; 2·ai ≤ |s|) — the position from which Pasha started transforming the string on the i-th day.
Output
s will look like after m
Sample test(s)
input
abcdef 1 2
output
aedcbf
input
vwxyz 2 2 2
output
vwxyz
input
abcdef 3 1 2 3
output
fbdcea
思路:因为按照题意所有的翻转都是按照中心对称翻,也就是说可以把翻转的次数记录下来,如果能被2整除就说明通过翻转他又回到了原来的地方,如果不能被整除就翻转一次。最后输出字符串。
#include<iostream>
#include<algorithm>
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
using namespace std;
int a[210000];
char str[210000];
int n,m;
int main()
{
while(scanf("%s",str)!=EOF)
{
scanf("%d",&n);
memset(a,0,sizeof(a));
int x;
for(int i=0;i<n;i++)
{
scanf("%d",&x);
a[x-1]++;
}
int l = strlen(str);
for(int i=1;i<=l/2;i++)
{
a[i] += a[i-1];
}
for(int i=0;i<l/2;i++)
{
if(a[i]%2 != 0)
{
char t = str[i];
str[i] = str[l-1-i];
str[l-1-i] = t;
}
}
printf("%s\n",str);
}
return 0;
}