下一个更大元素系列

Leetcode/L496.cpp

@@ -0,0 +1,27 @@
+#include <iostream>
+#include <map>
+#include <stack>
+#include <vector>
+using namespace std;
+
+class Solution {
+   public:
+    vector<int> nextGreaterElement(vector<int>& nums1, vector<int>& nums2) {
+        vector<int> ans;
+        stack<int> s;
+        map<int, int> m;
+        for (int i = 0; i < nums2.size(); i++) {
+            while (!s.empty() && s.top() < nums2[i]) {
+                m[s.top()] = nums2[i];
+                s.pop();
+            }
+            s.push(nums2[i]);
+        }
+        for (int i = 0; i < nums1.size(); i++) {
+            ans.emplace_back(m.count(nums1[i]) ? m[nums1[i]] : -1);
+        }
+        return ans;
+    }
+};
+
+int main() { return 0; }

Leetcode/L503.cpp

@@ -0,0 +1,24 @@
+#include <iostream>
+#include <map>
+#include <stack>
+#include <vector>
+using namespace std;
+
+class Solution {
+   public:
+    vector<int> nextGreaterElements(vector<int>& nums) {
+        int len = nums.size();
+        stack<int> s;
+        vector<int> ans(len, -1);
+        for (int i = 0; i < 2 * len; i++) {
+            while (!s.empty() && nums[s.top()] < nums[i % len]) {
+                ans[s.top()] = nums[i % len];
+                s.pop();
+            }
+            s.push(i % len);
+        }
+        return ans;
+    }
+};
+
+int main() { return 0; }

Leetcode/L556.cpp

@@ -0,0 +1,40 @@
+#include <iostream>
+#include <map>
+#include <stack>
+#include <vector>
+using namespace std;
+
+class Solution {
+   public:
+    int nextGreaterElement(int n) {
+        if (n == 0 || n > INT_MAX) return -1;
+        vector<int> digits;
+        while (n > 0) {
+            digits.push_back(n % 10);
+            n = n / 10;
+        }
+        int i = 1;
+        while (i < digits.size() && digits[i] >= digits[i - 1])
+            i++;  // 从右往左，找到第一个不是递增的位数
+        if (i == digits.size()) return -1;
+        int j = 0;
+        while (digits[j] <= digits[i]) j++;
+        swap(digits[i], digits[j]);
+        sort(digits.begin(), digits.begin() + i);
+        reverse(digits.begin(), digits.begin() + i);
+        long ret = 0;
+        for (int k = digits.size() - 1; k >= 0; k--) {
+            ret = ret * 10 + digits[k];
+        }
+        if (ret > INT_MAX)
+            return -1;
+        else
+            return ret;
+    }
+};
+// https://youtu.be/OKNpknDO86U
+int main() {
+    Solution INSTANCE;
+    cout << INSTANCE.nextGreaterElement(37986251) << endl;
+    return 0;
+}