太阳好大我好怕

在连续两晚上热哭了之后，好不容易呼吁寝室交了空调租赁费，修空调的人修好之后拔腿就跑，发现空调是烂的，现在让他来修结果他还紧都拖。

这两天天天往106跑，不是说他们寝室氛围有多浓厚，就是单纯的想蹭个空调，都要蹭到不好意思了。

不说了先看题。

这个题我当时一直想用队列做，然后失败了，愤懑的我就洗头去了。

其实就是substr的用法，掌握了差不多就能搞出来，以后不许自己这么菜。

A. Many Equal Substrings

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

You are given a string $\mathrm{tt consisting\; of nn lowercase\; Latin\; letters\; and\; an\; integer\; number kk.}$

Let's define a substring of some string $\mathrm{ss with\; indices\; from ll to rr as s[l\dots r]s[l\dots r].}$

Your task is to construct such string $\mathrm{ss of\; minimum\; possible\; length\; that\; there\; are\; exactly kk positions ii such\; that s[i\dots i+n-1]=ts[i\dots i+n-1]=t.\; In\; other\; words,\; your\; task\; is\; to\; construct\; such\; string ss of\; minimum\; possible\; length\; that\; there\; are\; exactly kk substrings\; of ss equal\; to tt.}$

It is guaranteed that the answer is always unique.

Input

The first line of the input contains two integers $\mathrm{nn and kk (1\le n,k\le 501\le n,k\le 50)\; —\; the\; length\; of\; the\; string tt and\; the\; number\; of\; substrings.}$

The second line of the input contains the string $\mathrm{tt consisting\; of\; exactly nn lowercase\; Latin\; letters.}$

Output

Print such string $\mathrm{ss of\; minimum\; possible\; length\; that\; there\; are\; exactly kk substrings\; of ss equal\; to tt.}$

It is guaranteed that the answer is always unique.

Examples

input

Copy

3 4
aba

output

Copy

ababababa

input

Copy

3 2
cat

output

Copy

catcat

#include<cstdio>
#include<iostream>
#include<cstring>
#include<string>
#include<vector>

using namespace std;

int main()
{
    int n, m,i,temp;
    string s;
    cin >> n >> m >> s;
    for(i=0;i<n;i++)
    {
        if(s.substr(0,i)==s.substr(n-i,i))
        {
            temp=i;
        }
    }
    for(i=1;i<m;i++)
        cout<<s.substr(0,n-temp);
    cout<<s<<endl;
    return 0;
}

 这个题就是贪心。找到最大次大的左端点和最小次小的右端点比较即可。

C. Maximal Intersection

time limit per test

3 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

You are given $\mathrm{nn segments\; on\; a\; number\; line;\; each\; endpoint\; of\; every\; segment\; has\; integer\; coordinates.\; Some\; segments\; can\; degenerate\; to\; points.\; Segments\; can\; intersect\; with\; each\; other,\; be\; nested\; in\; each\; other\; or\; even\; coincide.}$

The intersection of a sequence of segments is such a maximal set of points (not necesserily having integer coordinates) that each point lies within every segment from the sequence. If the resulting set isn't empty, then it always forms some continuous segment. The length of the intersection is the length of the resulting segment or $\mathrm{00 in\; case\; the\; intersection\; is\; an\; empty\; set.}$

For example, the intersection of segments $[1;5][1;5] and [3;10][3;10] is [3;5][3;5] (length 22),\; the\; intersection\; of\; segments [1;5][1;5] and [5;7][5;7] is [5;5][5;5](length 00)\; and\; the\; intersection\; of\; segments [1;5][1;5] and [6;6][6;6] is\; an\; empty\; set\; (length 00).$

Your task is to remove exactly one segment from the given sequence in such a way that the intersection of the remaining $(n-1)(n-1)segments\; has\; the\; maximal\; possible\; length.$

Input

The first line contains a single integer $\mathrm{nn (2\le n\le 3\cdot 1052\le n\le 3\cdot 105)\; —\; the\; number\; of\; segments\; in\; the\; sequence.}$

Each of the next $\mathrm{nn lines\; contains\; two\; integers lili and riri (0\le li\le ri\le 1090\le li\le ri\le 109)\; —\; the\; description\; of\; the ii-th\; segment.}$

Output

Print a single integer — the maximal possible length of the intersection of $(n-1)(n-1) remaining\; segments\; after\; you\; remove\; exactly\; one\; segment\; from\; the\; sequence.$

Examples

input

Copy

4
1 3
2 6
0 4
3 3

output

Copy

1

input

Copy

5
2 6
1 3
0 4
1 20
0 4

output

Copy

2

input

Copy

3
4 5
1 2
9 20

output

Copy

0

input

Copy

2
3 10
1 5

output

Copy

7

By authentic, contest: Codeforces Round #506 (Div. 3), problem: (C) Maximal Intersection, Accepted, #
 #include <iostream>
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
using namespace std;
struct node
{
    int x;
    int y;
}a[300001];
bool cmp(int x,int y)
{
    return x>y;
}
int x[300001],y[300001];
int main()
{
 int n,i;
 cin>>n;
 for(i=0;i<n;i++)
 {
    cin>>a[i].x>>a[i].y;
   x[i]=a[i].x;
   y[i]=a[i].y;
}
sort(x,x+n,cmp);
sort(y,y+n);
int l1=x[0],l2=x[1];
int r1=y[0],r2=y[1];
for(i=0;i<n;i++)
{
    if(a[i].x==l1&&a[i].y==r1)
    {
        cout<<r2-l2<<endl;
        return 0;
    }
}
cout<<max(0,max(r1-l2,r2-l1))<<endl;
return 0;
}

这道题就有点巧妙了，他让你算中间间隔为n的倍数的为1的位置，那么我们就对n取余，余数相同者满足条件

There is a long fence not far from H &H office. A while ago boards of the fence were painted in different colors. Now H &H CTO wants to know, if there are two red boards in the fence with the number of boards between them multiple to K.

Input

The first line contains the integer number K (1 ≤ K ≤ 100000). The second line contains the description of the fence. Symbol ——"1" indicates the red board, and symbol "0" —— any other. The fence contains not more than 100000 boards.

Output

Output the numbers of required boards, or output two zeros if they do not exist. Boards are numbered starting with 1 from left to right.

Sample Input

3
00101000010

Sample Output

3 10

#include <iostream>
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
using namespace std;
int a[100010];
int main()
{
 int n,i,j;
 char s[100010];
 cin>>n;
 scanf("%s",s+1);
 int len=strlen(s+1);
 for(i=1;i<=len;i++)
 {
     if(s[i]=='1')
     {
         if(a[(i-1)%n])
         {
            cout<<a[(i-1)%n]<<" "<<i<<endl;
         return 0;
         }
           a[i%n]=i;
     }
 }
 cout<<0<<" "<<0<<endl;
 return 0;
}

修空调的人快来！不然我就画个圈圈诅咒你。。。