Create 2280.Minimum-Lines-to-Represent-a-Line-Chart.cpp

Author: wisdompeak

Math/2280.Minimum-Lines-to-Represent-a-Line-Chart/2280.Minimum-Lines-to-Represent-a-Line-Chart.cpp

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+class Solution {
+public:
+ int minimumLines(vector<vector<int>>& stockPrices) 
+ {
+ if (stockPrices.size()==1) return 0;
+ sort(stockPrices.begin(), stockPrices.end());
+ 
+ int ret = 1;
+ int n = stockPrices.size();
+ for (int i=2; i<n; i++)
+ {
+ if (!checkAlign(stockPrices, i))
+ ret++;
+ }
+ return ret; 
+ }
+ 
+ bool checkAlign(vector<vector<int>>& stockPrices, int t)
+ {
+ int x0 = stockPrices[t-2][0], y0 = stockPrices[t-2][1];
+ int x1 = stockPrices[t-1][0], y1 = stockPrices[t-1][1];
+ int x2 = stockPrices[t-0][0], y2 = stockPrices[t-0][1];
+ 
+ return (long long)(y2-y1)*(x1-x0)==(long long)(y1-y0)*(x2-x1);
+ }
+};