From 2a7bc10f6c011d19fb3b0e73068f7e1a9c30ace0 Mon Sep 17 00:00:00 2001 From: Raphael McSinyx Date: Sat, 8 Oct 2016 09:56:43 +0700 Subject: Initial commit --- 10/CSP-KT2/negpairs.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) create mode 100644 10/CSP-KT2/negpairs.c (limited to '10/CSP-KT2/negpairs.c') diff --git a/10/CSP-KT2/negpairs.c b/10/CSP-KT2/negpairs.c new file mode 100644 index 0000000..577fdf8 --- /dev/null +++ b/10/CSP-KT2/negpairs.c @@ -0,0 +1,24 @@ +#include + +int main() +{ + long n, i; + long unsigned_a[201] = {}; + long *a = &unsigned_a[100]; + char a0; + long long v; + + scanf("%ld", &n); + for (i = 0; i < n; i++) { + scanf("%hhd", &a0); + a[a0]++; + } + + v = a[0] * (a[0] - 1) / 2; + for (i = 1; i <= 100; i++) + v += a[i] * a[-i]; + + printf("%lld\n", v); + + return 0; +} -- cgit 1.4.1