You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
33 lines
651 B
33 lines
651 B
2 years ago
|
package class35;
|
||
|
|
|
||
|
|
import java.util.HashMap;
|
||
|
|
|
||
|
|
public class Problem_0454_4SumII {
|
||
|
|
|
||
|
|
public static int fourSumCount(int[] A, int[] B, int[] C, int[] D) {
|
||
|
|
HashMap<Integer, Integer> map = new HashMap<>();
|
||
|
|
int sum = 0;
|
||
|
|
for (int i = 0; i < A.length; i++) {
|
||
|
|
for (int j = 0; j < B.length; j++) {
|
||
|
|
sum = A[i] + B[j];
|
||
|
|
if (!map.containsKey(sum)) {
|
||
|
|
map.put(sum, 1);
|
||
|
|
} else {
|
||
|
|
map.put(sum, map.get(sum) + 1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
int ans = 0;
|
||
|
|
for (int i = 0; i < C.length; i++) {
|
||
|
|
for (int j = 0; j < D.length; j++) {
|
||
|
|
sum = C[i] + D[j];
|
||
|
|
if (map.containsKey(-sum)) {
|
||
|
|
ans += map.get(-sum);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return ans;
|
||
|
|
}
|
||
|
|
|
||
|
|
}
|