class Solution {
public int maxEnvelopes(int[][] envelopes) {
int ans = 1;
if (envelopes == null || envelopes.length == 0 || envelopes[0].length != 2)
return 0;
Arrays.sort(envelopes, new Comparator<int[]>(){
@Override
// 先按照长递增排序(当长相同时按照宽递减排序)
public int compare(int[] e1, int[] e2) {
if (e1[0] == e2[0]) {
return e2[1] - e1[1];
} else {
return e1[0] - e2[0];
}
}
});
int[] dp = new int[envelopes.length];
dp[0] = 1;
for (int i = 1; i < envelopes.length; i++) {
dp[i] = 1;
for (int j = 0; j < i; j++) {
if (envelopes[i][1] > envelopes[j][1]) {
dp[i] = Math.max(dp[i], dp[j] + 1);
}
}
ans = Math.max(ans, dp[i]);
}
return ans;
}
}