Initial commit

15lanqiao/test4.cpp

@@ -0,0 +1,34 @@
+#include<bits/stdc++.h>
+using namespace std;
+const int N = 2e3 + 10;
+string s; int a[N];
+int main() {
+	int n; cin >> n >> s;
+    reverse(s.begin(), s.end());
+    int pos = s.find(".");  //  小数点位置
+    s.erase(pos, 1); // 删除小数点, 方便后续计算
+    int len = s.size();
+    for(int i = 0; i < len; i++) a[i+1] = s[i] - '0';
+// a[1] = 4，a[2] = 1，a[3] = 3
+
+    //高精度*低精度模版
+    for(int i = 1; i<=n; i++){
+        // 顺序扫描每一位, 均乘2
+        for(int j = 1; j <= len; j++) a[j] *= 2;
+        for(int j = 1; j <= len; j++){
+            if(a[j] > 10){
+                a[j+1]++;
+                a[j] %= 10;
+                if(j == len) len++;
+            }
+        }
+    }
+// a[1] = 6，a[2] = 5，a[3] = 2，a[4] = 1  a[pos] = 5
+    if(a[pos] >= 5) a[pos+1]++;
+    for(int i = len; i >= pos + 1; i--) cout << a[i];
+    cout << endl;
+	return 0;
+}
+/*
+2 3.14
+*/