单调栈版子
1 #include<cstdio> 2 #include<cstring> 3 using namespace std; 4 const int N=80010; 5 int n,a,top=0,zh[N]; 6 int read(){ 7 int sum=0; 8 char ch=getchar(); 9 while (ch<'0'||ch>'9') 10 ch=getchar(); 11 while (ch>='0'&&ch<='9'){ 12 sum=sum*10+ch-'0'; 13 ch=getchar(); 14 } 15 return sum; 16 } 17 int main(){ 18 long long ans=0; 19 scanf("%d",&n); 20 for (int i=1;i<=n;i++){ 21 a=read(); 22 while (a>=zh[top]&&top) top--; 23 ans+=top; 24 zh[++top]=a; 25 } 26 printf("%lld",ans); 27 return 0; 28 }
