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feat: usage of __builtin_clz

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Lam Haoyin 2022-01-02 11:28:22 +08:00
parent 706548af13
commit 08e310e19d
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1 changed files with 3 additions and 2 deletions
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2201/220102-CN.cpp
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@ -4,8 +4,9 @@ class Solution {
public: public:
// O(log(n)) // O(log(n))
static int lastRemaining(int n) { static int lastRemaining(int n) {
int cnt = 0, ret = 1; // int cnt = 0, ret = 1;
for (int i = n; i >>= 1; ++cnt); int ret = 1, cnt = __builtin_clz(n) ^ 31;
// for (int i = n; i >>= 1; ++cnt);
for (int i = 0; i < cnt; ++i, n >>= 1) for (int i = 0; i < cnt; ++i, n >>= 1)
ret += !(1 & i) || (1 & n) ? (1 << i) : 0; ret += !(1 & i) || (1 & n) ? (1 << i) : 0;
return ret; return ret;