更新 837和238

Author: LuYanFCP

cpp/238.cpp

@@ -0,0 +1,18 @@
+#include <vector>
+using namespace std;
+
+class Solution {
+public:
+    vector<int> productExceptSelf(vector<int>& nums) {
+        int n = nums.size();
+        vector<int> res(n, 1);
+        int pre = 1, post = 1;
+        for (int i = 1, j = n-1; i < n; ++i) {
+            res[i] *= pre;
+            res[j] *= post;
+            pre *= res[i];
+            post *= res[j];
+        } // 正着求
+        return res;
+    }
+};

cpp/837.cpp

@@ -0,0 +1,27 @@
+#include <algorithm>
+using namespace std;
+class Solution {
+public:
+    double new21Game(int N, int K, int W) {
+        // vector<double> dp(K+W+1, 0.0);
+        double dp[20000+1];
+        fill(dp, dp+20000+1, 0.0);
+        double _sum = N-K+1;
+        for (int i = K; i <= N ; ++i) {
+            dp[i] = 1.0;
+            // _sum += 1.0;
+        }
+            
+
+        for (int i = K-1; i >= 0; --i) {
+            // 问题出在这
+            // for (int j = i+1; j <= i+W; ++j) {
+            //     _sum += dp[j];
+            // }
+            dp[i] = _sum * 1/W;
+            // printf("%d-%f--dp[i]=%f\n", i+W, dp[i+W-1], _sum);
+            _sum = _sum - dp[i+W] + dp[i];
+        }
+        return dp[0];
+    }
+};

python/238.py

@@ -0,0 +1,12 @@
+class Solution:
+    def productExceptSelf(self, nums: List[int]) -> List[int]:
+        n = len(nums)
+        res = [1] * n
+        l, r = 1, 1
+        for i in range(0, n):
+            j = n - i - 1
+            res[i] *= l
+            res[j] *= r
+            l *= nums[i]
+            r *= nums[j]
+        return res