790. 数的三次方根

https://www.acwing.com/problem/content/submission/code_detail/6595736/

AcWing/790/790.cpp

@@ -0,0 +1,21 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+double n, l, r;
+
+int main() {
+    cin >> n;
+    l = -100.00;
+    r = 100.00;
+    while (r - l > 1e-8) {
+        double mid = (l + r) / 2;
+        if (mid * mid * mid >= n) {
+            r = mid;
+        } else {
+            l = mid;
+        }
+    }
+    cout << fixed << setprecision(6) << l << endl;
+    return 0;
+}