Idea is to check whether the input data after input legitimate (lost) or the first one way, then the accumulative sum of input data and then 1 + 2 +... + N sumN is take over, don't know what is wrong,

 
# include & lt; Bits/stdc++. H> 
using namespace std; 

Int main () {
Unsigned int T; 
Long long N; 
Long long sum=0, sumN=0; 
Int sign=1; 
Cin & gt;> T; 
Int ans [T]; 
for (int i=0; I & lt; T; + + I) {
Cin & gt;> N; 
Vector Num. 
Long long input; 
Sum=sumN=0; 
Sign=1; 
Unsigned int numCount [N]={0}; 
For (int j=1; J & lt;=N; SumN +=j + + j); 
For (int j=0; J & lt; N; + + j) {
Cin & gt;> The input; 
Num. Push_back (input); 
NumCount [num [j] - 1] + +; 
} 
Unsigned int numCountAll=0; 
For (int j=N - 1; J & gt;=0; - j) {
NumCountAll +=numCount [j]; 
If (numCountAll & gt; N - j) {
Sign=0; 
break; 
} 
} 
If (sign==0) {
Ans [I]=0; 
} else {
For (int j=0; J & lt; N; + + j) {
The sum + num=[j]; 
} 
Int sub=sumN - sum; 
If (sub % 2==1) {
Ans [I]=1; 
} else {
Ans [I]=0; 
} 
} 
} 
for (int i=0; I & lt; T; + + I) {
If (ans [I]) {
Printf (" First \ n "); 
} else {
Printf (" Second \ n "); 
} 
} 
return 0; 
}