Algorithm

problem link- https://www.spoj.com/problems/MADODDSUM/

MADODDSUM - Easy Odd Sum

#simple-math

 

Hablu likes odd numbers a lot. So he wants the sum of all odd numbers in range [a, b]. That is, find the sum of all odd numbers i such that (a ≤ i ≤ b). Seems easy right? Because it is.

Input

The first and only line will contain 2 integers a, b where (0 ≤ a ≤ 108) and (0 ≤ b ≤ 108).

Output

In one line, output the value of the sum

Example

Input:
0 9

Output:
25

 

Code Examples

#1 Code Example with Python Programming

Code - Python Programming

def get(n):
    n = (n + 1) // 2
    return n * n
a, b = map(int, input().split())
if a % 2 == 1:
    a -= 1
print(get(b) - get(a))
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Input

x
–
+
cmd
0 9

Output

x
–
+
cmd
25

#2 Code Example with C++ Programming

Code - C++ Programming

#include <algorithm>
#include <iostream>
#include <fstream>
#include <sstream>
#include <cstring>
#include <cstdlib>
#include <cstdarg>
#include <utility>
#include <cctype>
#include <cstdio>
#include <vector>
#include <string>
#include <cmath>
#include <ctime>
#include <queue>
#include <deque>
#include <stack>
#include <set>
#include <map>

using namespace std;

typedef long long LL;
typedef vector<int> vint;
typedef pair<int,int> pint;
typedef unsigned long long ULL;

short CC_;
#define sf scanf
#define pf printf
#define NL pf("\n");
#define dcc (double)
#define PP getchar();
#define SS printf(">_<LOOOOOK@MEEEEEEEEEEEEEEE<<( %d )>>\n",++CC_);
#define DD(x_) cout<<">>>>( "<<++CC_<<" ) "<<#x_<<": "<<x_<<endl;
#define EXT(st_) cout<<"\n>>>Exicution Time: "<<(double)(clock()-st_)/CLOCKS_PER_SEC<<endl;

//constants
const int SZ= 1E6;
const int INF= (1<<29);
const double EPS= 1E-9;
const double PI= 2*acos(0.0);



void solve(void)
{
    ULL a,b;
    
    cin>>a>>b;
    
    if(a%2 == 0) a++;
    if(b%2 == 0) b--;
    
    int n= (b - a)/2 +1;
    LL sum= (n* (2*a + (n-1)*2))/2;
    
    cout<< sum <<endl;
}


int main(void)
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    solve();
    
    return 0;
}
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Input

x
–
+
cmd
0 9

Output

x
–
+
cmd
25
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Demonstration

SPOJ Solution-Easy Odd Sum-Solution in C, C++, Java, Python

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