Add C++ solution for leetcode 435.

Author: yanglr

cpp-leetcode/leetcode435-non-overlapping-intervals_greedy.cpp

@@ -0,0 +1,39 @@
+#include<vector>
+#include<algorithm>
+#include<iostream>
+using namespace std;
+
+class Solution {
+public:
+    int eraseOverlapIntervals(vector<vector<int>>& R) { /* R: 代表ranges */
+        auto cmp = [](const vector<int>& p1, const vector<int>& p2)
+        {
+            return p1[1] < p2[1];
+        };
+        sort(R.begin(), R.end(), cmp);
+        const int len = R.size();
+        if (R.empty()) return 0;
+        int maxRemain = 1; // maxRemain: 最多保留下来多少个区间
+        int curRight = R[0][1];
+        for (int i = 1; i < len; i++)
+        {
+            if (R[i][0] >= curRight) /* 新来的区间的左边界R[i][0] 与当前区间的右边界比较, 如果≥成立说明可以再留下1个新的区间 */
+            {
+                maxRemain++;
+                curRight = R[i][1];
+            }
+        }    
+        return len - maxRemain;
+    }
+};
+
+// Test
+int main()
+{
+    Solution sol;
+    vector<vector<int>> ranges = {{1, 2}, {2, 3}, {3, 4}, {1, 3}};
+    auto res = sol.eraseOverlapIntervals(ranges);
+    cout << res << endl;
+
+    return 0;
+}