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30 lines
678 B
C++

#define _CRT_SECURE_NO_WARNINGS
#define _SILENCE_CXX17_C_HEADER_DEPRECATION_WARNING
#include <bits/stdc++.h>
using namespace std;
const int N = 1 << 10;
int w[N], b[N];
int p[N];
bool u[N];
int main()
{
int n, m;
scanf("%d%d", &n, &m);
for (int i = 1; i <= n; i++)
scanf("%d", w + i);
for (int i = 1; i <= m; i++)
scanf("%d", b + i);
memset(p, 0, sizeof(p));
long long ans = 0;
for (int i = 1; i <= m; i++)
{
memset(u, 0, sizeof(u));
for (int j = p[b[i]] + 1; j < i; j++)
if (!u[b[j]])
ans += w[b[j]], u[b[j]] = true;
p[b[i]] = i;
}
printf("%lld", ans);
return 0;
}