g0901_1000.s0927_three_equal_parts.Solution Maven / Gradle / Ivy
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Java-based LeetCode algorithm problem solutions, regularly updated
package g0901_1000.s0927_three_equal_parts;
// #Hard #Array #Math #2022_03_29_Time_2_ms_(90.20%)_Space_47.4_MB_(96.08%)
public class Solution {
public int[] threeEqualParts(int[] arr) {
int ones = 0;
for (int num : arr) {
ones += num;
}
if (ones == 0) {
return new int[] {0, 2};
} else if (ones % 3 != 0) {
return new int[] {-1, -1};
}
ones /= 3;
int index1 = -1;
int index2 = -1;
int index3 = -1;
int totalOnes = 0;
for (int i = 0; i < arr.length; i++) {
if (arr[i] == 0) {
continue;
}
totalOnes += arr[i];
if (totalOnes == 1) {
index1 = i;
} else if (totalOnes == ones + 1) {
index2 = i;
} else if (totalOnes == 2 * ones + 1) {
index3 = i;
}
}
while (index3 < arr.length) {
if (arr[index1] == arr[index3] && arr[index2] == arr[index3]) {
++index1;
++index2;
++index3;
} else {
return new int[] {-1, -1};
}
}
return new int[] {index1 - 1, index2};
}
}