class Solution {public:    /**     *@param n, m: Two integer     *@param i, j: Two bit positions     *return: An integer     */    int updateBits(int n, int m, int i, int j) {        if (i == 0 && j == 31) return m;                int cnt = j - i + 1;        int mask = (1 << cnt) - 1;        int nn = (n >> i) & mask;        n ^= (nn << i); // clear        n |= (m << i); // set                return n;    }};