bestcoder#43 1002 Find two numbers in the array and modulo the maximum value of two points

bestcoder#43 1002 Find two numbers in the array and the maximum value of modulo two pog loves Szh IIaccepts:97submissions:834Time limit:4000/2000 MS (java/others)Memory limit:65536/65536 K (java/others)Problem Description

Pog and Szh is playing games. There is a sequence withN numbers, pog will choose a number a from the sequence.  szh will choose an Another number named b from the rest  in the sequence. Then the score will be  (A+B) mod p. They hope to get the largest score. and what is the largest score?

Input

Several groups of data (no more than 5 groups,n≥).

For each case:

The following line contains and integers,n(2≤n≤100000) ， P(1≤p≤2−1) .

The following line containsNIntegers Ai ( 0≤ a I≤ 231−1) .

Output

For each case,output an integer means the largest score.

Sample Input

4 41 2 3 04 40 0 2 2

Sample Output

32
Test instructions: Given the array A and integer p, find the two number in the array, a, B, so that (a+b)%p maximum, output maximum value.
Idea: The number of all inputs to modulo, sort, then to any two in the array of the number of a, a, there is 0<=a<=p-1,0<=b<=p-1, that is, 0<=a+b<=2*p-2, so (a+b)%p maximum when there are two cases, namely a+b <p,a+b is less than but closest to P, the other is a+b>p, that is, a+b is less than, but closest to, 2*p maximum. Move the item, fix A, find the first number less than P-a, and the first number less than 2*p-a, and take the optimal one.

#include <iostream>#include<cstdio>#include<cstring>#include<cstdlib>#include<algorithm>#include<vector>#include<stack>#include<queue>#include<Set>#include<map>#include<string>#include<math.h>#include<cctype>using namespaceStd;typedefLong Longll;Const intmaxn=1000100;Const intInf= (1<< in);Const Doubleeps=0.0000000001;Const DoublePi=acos (-1.0); ll n,p;ll A[maxn];ll Bin_search (intLeftintright,ll Key) {     while(left<=Right ) {        intMid= (left+right)/2; //cout<<left<< "" <<right<< "" <<mid<<endl;        if(A[mid]>key) right=mid-1; Else if((Mid==n&&a[mid]<=key) | | (a[mid+1]>key&&a[mid]<=key))returnA[mid]; ElseLeft=mid+1; }    return-INF;}intMain () { while(cin>>n>>p) {         for(intI=1; i<=n;i++) {scanf ("%i64d",&A[i]); A[i]%=p; } sort (A+1, a+n+1); ll ans=0;  for(intI=1; i<=n-1; i++) {ll x=bin_search (i+1, n,p-A[i]); ll y=bin_search (i+1N2*p-A[i]); //cout<< "i+1=" <<i+1<< "p-a[i]=" <<p-a[i]<<endl; //cout<< "x=" <<x<< "y=" <<y<<endl;ll T=max ((X+a[i])%p, (Y+a[i])%p); if(T>ans) ans=T; } cout<<ans<<Endl; }    return 0;}

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bestcoder#43 1002 Find two numbers in the array and modulo the maximum value of two points