UVALive 6527 Counting ones dfs（水

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#include <cstdio>#include <vector>using namespace std;typedef long long ll;ll re;vector<int> p;void dfs(int dep, int g) {if (dep == 0)return ;if (p[dep-1] == 1) {re += (dep-1) * (1ll<< (dep-2));re += g * (1ll << (dep-1));}dfs(dep-1, g+p[dep-1]);}ll C(ll x) {if (x == 0)return 0;p.clear();re = 0;while (x>0) {p.push_back(x%2);x /= 2;}for (int i = 0; i < (int)p.size(); ++i)re += p[i];dfs(p.size(), 0);return re;}int main() {ll A, B;while (~scanf("%lld%lld", &A, &B))printf("%lld\n", C(B) - C(A-1));return 0;}