leetcode 之trap water（8）

int trapWater(int A[], int n)
{
int peak = 0;
int max = 0;
int water = 0;
for (int i = 1; i < n; i++)
{
if (A[i]>A[max])max = i;
}

for (int i = 0; i < max; i++)
{
if (A[i]>peak)
peak = A[i];
else
water += peak - A[i];
}

for (int j = n - 1; j > max; j--)
{
if (A[j]>peak)
peak = A[j];
else
water += peak - A[j];
}

return water;
}