'commit'

TangDou/AoSaiYiBenTong/YBT1034.cpp

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+#include <bits/stdc++.h>
+
+using namespace std;
+
+int main() {
+    //cin读入优化
+    std::ios::sync_with_stdio(false);
+
+    float x1, y1, x2, y2, x3, y3;
+    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
+
+    //求三条边的长度，然后再用海伦公式进行求解
+    double a, b, c;
+    a = sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
+    b = sqrt((x1 - x3) * (x1 - x3) + (y1 - y3) * (y1 - y3));
+    c = sqrt((x3 - x2) * (x3 - x2) + (y3 - y2) * (y3 - y2));
+
+    double p = (a + b + c) / 2;
+    //假设在平面内,有一个三角形,边长分别为a、b、c
+    //三角形的面积S可由以下公式求得：
+    //S=√[p(p-a)(p-b)(p-c)]
+    //而公式里的p为半周长：p=(a+b+c)/2
+    cout << fixed << setprecision(2) << sqrt(p * (p - a) * (p - b) * (p - c)) << endl;
+    return 0;
+}