hdu 1001(分治求解)

#include <cstdio>
#include <iostream>

using namespace std;

int solve(int l, int r) {
    if (l == r) return l;
    return solve(l, ((l+r)>>1)) + solve(((l+r)>>1)+1, r);
}

int main() {
    int n;
    while (scanf("%d", &n) != EOF) {
        int ans = solve(1, n);
        printf ("%d\n\n", ans);
    }
    return 0;
}