44 lines
946 B
C++
44 lines
946 B
C++
#include <iostream>
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using namespace std;
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int main()
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{
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int t;
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cin >> t;
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while(t--)
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{
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char buf[120];
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int n;
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cin >> n;
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int dz[22];
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for(int j = 0; j < n; j++)
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{
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int cnt = 0;
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int a=0, sum = 0;
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getchar();
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gets(buf);
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int len = strlen(buf);
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for(int i = 0; i < len; i++)
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{
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if(isdigit(buf[i]))
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{
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a = a * 10 + buf[i] - '0';
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}
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else
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{
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sum += a;
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a = 0;
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}
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}
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dz[j] = sum;
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}
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double result = 0;
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for(int i = 0 ; i < n; i++)
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{
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result += 1.0 / dz[i];
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}
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result = 1.0 / result;
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printf("%.2lf\n", result);
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}
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return 0;
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}
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