OJ-Problems-Source/HDOJ/5419_autoAC.cpp

47 lines
1.1 KiB
C++
Raw Normal View History

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std ;
#define LL __int64
LL dp[50100] ;
int a[50100] ;
LL gcd(LL a,LL b) {
return b == 0 ? a : gcd(b,a%b) ;
}
int main() {
int t , n , m ;
int i , l , r ;
LL x , y , temp ;
scanf("%d", &t) ;
while( t-- ) {
scanf("%d %d", &n, &m) ;
memset(dp,0,sizeof(dp)) ;
for(i = 1 ; i <= n ; i++)
scanf("%d", &a[i]) ;
while( m-- ) {
scanf("%d %d", &l, &r) ;
dp[l]++ ;
dp[r+1]-- ;
}
x = 0 ;
y = (LL)n*(n-1)*(n-2)/6 ;
for(i = 1 ; i <= n ; i++) {
dp[i] += dp[i-1] ;
if( dp[i] > 2 )
x += dp[i]*(dp[i]-1)*(dp[i]-2)/6*a[i] ;
}
if( x == 0 || y == 0 ) {
printf("0\n") ;
continue ;
}
temp = gcd(x,y) ;
x /= temp ;
y /= temp ;
if( y == 1 )
printf("%I64d\n", x ) ;
else
printf("%I64d/%I64d\n", x, y) ;
}
return 0 ;
}