See this article on my own blog https://dyingdown.github.io/2020/01/30/CodeForces-1295A-Display-The-Number/
You have a large electronic screen which can display up to 998244353 998244353 998244353 decimal digits. The digits are displayed in the same way as on different electronic alarm clocks: each place for a digit consists of 7 7 7 segments which can be turned on and off to compose different digits. The following picture describes how you can display all 10 10 10 decimal digits:
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As you can see, different digits may require different number of segments to be turned on. For example, if you want to display 1 1 1, you have to turn on 2 2 2 segments of the screen, and if you want to display 8 8 8, all 7 7 7 segments of some place to display a digit should be turned on.
You want to display a really large integer on the screen. Unfortunately, the screen is bugged: no more than n n n segments can be turned on simultaneously. So now you wonder what is the greatest integer that can be displayed by turning on no more than n n n segments.
Your program should be able to process t t t different test cases.
Input
The first line contains one integer t ( 1 ≤ t ≤ 100 ) t (1≤t≤100) t(1≤t≤100) — the number of test cases in the input.
Then the test cases follow, each of them is represented by a separate line containing one integer n ( 2 ≤ n ≤ 105 ) n (2≤n≤105) n(2≤n≤105) — the maximum number of segments that can be turned on in the corresponding testcase.
It is guaranteed that the sum of n n n over all test cases in the input does not exceed 105 105 105.
Output
For each test case, print the greatest integer that can be displayed by turning on no more than n n n segments of the screen. Note that the answer may not fit in the standard 32 32 32-bit or 64 64 64-bit integral data type.
Example
input
2
3
4
output
7
11
Analysis
The more number it can lighten, the longer digits it can have. So,
1 1 1 uses the less segments.
We make 1 1 1 as many as possible. If there are still segments left that can’t make a complete 1 1 1, we break up one 1 1 1 and let it form 7 7 7 with the rest.(the rest could only be 1 or 0 because 1 1 1 uses two segments)
Code
#include<bits/stdc++.h>
using namespace std;
int main() {
int t;
cin >> t;
while (t--) {
int n;
cin >> n;
int digits1 = n / 2;
if(n % 2 == 1) {
cout << 7;
for(int i = 1; i < digits1; i ++) {
cout << 1;
}
} else {
for(int i = 0; i < digits1; i ++) {
cout << 1;
}
}
cout << endl;
}
return 0;
}