Create minimum-lines-to-represent-a-line-chart.cpp

Author: kamyu104

C++/minimum-lines-to-represent-a-line-chart.cpp

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+// Time:  O(nlogn)
+// Space: O(1)
+
+// sort, math, gcd
+class Solution {
+public:
+    int minimumLines(vector<vector<int>>& stockPrices) {
+        int result =0;
+        sort(begin(stockPrices), end(stockPrices));
+        vector<int> prev;
+        for (int i = 1; i < size(stockPrices); ++i) {
+            const int dy = stockPrices[i][1] - stockPrices[i - 1][1];
+            const int dx = stockPrices[i][0] - stockPrices[i - 1][0];
+            const int g = gcd(dy, dx);
+            if (empty(prev) || prev != vector<int>({dy / g, dx / g})) {
+                prev = {dy / g, dx / g};
+                ++result;
+            }
+        }
+        return result;
+    }
+};