00100 - The 3n + 1 problem

#include <cstdio>
#include <map>
using namespace std;

map<int, int> table;

int calc(int n) {
    int m = table[n];
    if(m) return m;
    return table[n] = (n&1)?2+calc((3*n+1)>>1):1+calc(n>>1);
}

int main() {
    table[1] = 1;
    for(int x, y; ~scanf("%d%d", &x, &y);) {
        printf("%d %d ", x, y);
        if(x > y) {
            int t = x; x = y; y = t;
        }
        int ans = 0;
        for(int i = x; i <= y; i++) {
            int l = calc(i);
            if(l > ans) ans = l;
        }
        printf("%d\n", ans);
    }
}