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Commitb81db41

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Improved task 3165
1 parent8d54924 commitb81db41

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1 file changed

+55
-103
lines changed
  • src/main/java/g3101_3200/s3165_maximum_sum_of_subsequence_with_non_adjacent_elements

1 file changed

+55
-103
lines changed
Lines changed: 55 additions & 103 deletions
Original file line numberDiff line numberDiff line change
@@ -1,125 +1,77 @@
11
packageg3101_3200.s3165_maximum_sum_of_subsequence_with_non_adjacent_elements;
22

33
// #Hard #Array #Dynamic_Programming #Divide_and_Conquer #Segment_Tree
4-
// #2024_06_02_Time_1927_ms_(87.75%)_Space_82.1_MB_(5.31%)
5-
6-
importjava.util.stream.Stream;
4+
// #2024_11_09_Time_64_ms_(100.00%)_Space_64.1_MB_(97.01%)
75

86
publicclassSolution {
7+
privatestaticfinalintYY =0;
8+
privatestaticfinalintYN =1;
9+
privatestaticfinalintNY =2;
10+
privatestaticfinalintNN =3;
911
privatestaticfinalintMOD =1_000_000_007;
1012

1113
publicintmaximumSumSubsequence(int[]nums,int[][]queries) {
12-
intans =0;
13-
SegTreesegTree =newSegTree(nums);
14-
for (int[]q :queries) {
15-
intidx =q[0];
16-
intval =q[1];
17-
segTree.update(idx,val);
18-
ans = (ans +segTree.getMax()) %MOD;
14+
long[][]tree =build(nums);
15+
longresult =0;
16+
for (inti =0;i <queries.length; ++i) {
17+
result +=set(tree,queries[i][0],queries[i][1]);
18+
result %=MOD;
1919
}
20-
returnans;
20+
return(int)result;
2121
}
2222

23-
staticclassSegTree {
24-
privatestaticclassRecord {
25-
inttakeFirstTakeLast;
26-
inttakeFirstSkipLast;
27-
intskipFirstSkipLast;
28-
intskipFirstTakeLast;
29-
30-
publicIntegergetMax() {
31-
returnStream.of(
32-
this.takeFirstSkipLast,
33-
this.takeFirstTakeLast,
34-
this.skipFirstSkipLast,
35-
this.skipFirstTakeLast)
36-
.max(Integer::compare)
37-
.orElse(null);
38-
}
39-
40-
publicIntegerskipLast() {
41-
returnStream.of(this.takeFirstSkipLast,this.skipFirstSkipLast)
42-
.max(Integer::compare)
43-
.orElse(null);
44-
}
45-
46-
publicIntegertakeLast() {
47-
returnStream.of(this.skipFirstTakeLast,this.takeFirstTakeLast)
48-
.max(Integer::compare)
49-
.orElse(null);
50-
}
23+
privatestaticlong[][]build(int[]nums) {
24+
finalintlen =nums.length;
25+
intsize =1;
26+
while (size <len) {
27+
size <<=1;
5128
}
52-
53-
privatefinalRecord[]seg;
54-
privatefinalint[]nums;
55-
56-
publicSegTree(int[]nums) {
57-
this.nums =nums;
58-
seg =newRecord[4 *nums.length];
59-
for (inti =0;i <4 *nums.length; ++i) {
60-
seg[i] =newRecord();
61-
}
62-
build(0,nums.length -1,0);
29+
long[][]tree =newlong[size *2][4];
30+
for (inti =0;i <len; ++i) {
31+
tree[size +i][YY] =nums[i];
6332
}
64-
65-
privatevoidbuild(inti,intj,intk) {
66-
if (i ==j) {
67-
seg[k].takeFirstTakeLast =nums[i];
68-
return;
69-
}
70-
intmid = (i +j) >>1;
71-
build(i,mid,2 *k +1);
72-
build(mid +1,j,2 *k +2);
73-
merge(k);
74-
}
75-
76-
// merge [2*k+1, 2*k+2] into k
77-
privatevoidmerge(intk) {
78-
seg[k].takeFirstSkipLast =
33+
for (inti =size -1;i >0; --i) {
34+
tree[i][YY] =
7935
Math.max(
80-
seg[2 *k +1].takeFirstSkipLast +seg[2 *k +2].skipLast(),
81-
seg[2 *k +1].takeFirstTakeLast +seg[2 *k +2].skipFirstSkipLast);
82-
83-
seg[k].takeFirstTakeLast =
36+
tree[2 *i][YY] +tree[2 *i +1][NY],
37+
tree[2 *i][YN] +Math.max(tree[2 *i +1][YY],tree[2 *i +1][NY]));
38+
tree[i][YN] =
8439
Math.max(
85-
seg[2 *k +1].takeFirstSkipLast +seg[2 *k +2].takeLast(),
86-
seg[2 *k +1].takeFirstTakeLast +seg[2 *k +2].skipFirstTakeLast);
87-
88-
seg[k].skipFirstTakeLast =
40+
tree[2 *i][YY] +tree[2 *i +1][NN],
41+
tree[2 *i][YN] +Math.max(tree[2 *i +1][YN],tree[2 *i +1][NN]));
42+
tree[i][NY] =
8943
Math.max(
90-
seg[2 *k +1].skipFirstSkipLast +seg[2 *k +2].takeLast(),
91-
seg[2 *k +1].skipFirstTakeLast +seg[2 *k +2].skipFirstTakeLast);
92-
93-
seg[k].skipFirstSkipLast =
44+
tree[2 *i][NY] +tree[2 *i +1][NY],
45+
tree[2 *i][NN] +Math.max(tree[2 *i +1][YY],tree[2 *i +1][NY]));
46+
tree[i][NN] =
9447
Math.max(
95-
seg[2 *k +1].skipFirstSkipLast +seg[2 *k +2].skipLast(),
96-
seg[2 *k +1].skipFirstTakeLast +seg[2 *k +2].skipFirstSkipLast);
97-
}
98-
99-
// child -> parent
100-
publicvoidupdate(intidx,intval) {
101-
inti =0;
102-
intj =nums.length -1;
103-
intk =0;
104-
update(idx,val,k,i,j);
105-
}
106-
107-
privatevoidupdate(intidx,intval,intk,inti,intj) {
108-
if (i ==j) {
109-
seg[k].takeFirstTakeLast =val;
110-
return;
111-
}
112-
intmid = (i +j) >>1;
113-
if (idx <=mid) {
114-
update(idx,val,2 *k +1,i,mid);
115-
}else {
116-
update(idx,val,2 *k +2,mid +1,j);
117-
}
118-
merge(k);
48+
tree[2 *i][NY] +tree[2 *i +1][NN],
49+
tree[2 *i][NN] +Math.max(tree[2 *i +1][YN],tree[2 *i +1][NN]));
11950
}
51+
returntree;
52+
}
12053

121-
publicintgetMax() {
122-
returnseg[0].getMax();
54+
privatestaticlongset(long[][]tree,intidx,intval) {
55+
intsize =tree.length /2;
56+
tree[size +idx][YY] =val;
57+
for (inti = (size +idx) /2;i >0;i /=2) {
58+
tree[i][YY] =
59+
Math.max(
60+
tree[2 *i][YY] +tree[2 *i +1][NY],
61+
tree[2 *i][YN] +Math.max(tree[2 *i +1][YY],tree[2 *i +1][NY]));
62+
tree[i][YN] =
63+
Math.max(
64+
tree[2 *i][YY] +tree[2 *i +1][NN],
65+
tree[2 *i][YN] +Math.max(tree[2 *i +1][YN],tree[2 *i +1][NN]));
66+
tree[i][NY] =
67+
Math.max(
68+
tree[2 *i][NY] +tree[2 *i +1][NY],
69+
tree[2 *i][NN] +Math.max(tree[2 *i +1][YY],tree[2 *i +1][NY]));
70+
tree[i][NN] =
71+
Math.max(
72+
tree[2 *i][NY] +tree[2 *i +1][NN],
73+
tree[2 *i][NN] +Math.max(tree[2 *i +1][YN],tree[2 *i +1][NN]));
12374
}
75+
returnMath.max(tree[1][YY],Math.max(tree[1][YN],Math.max(tree[1][NY],tree[1][NN])));
12476
}
12577
}

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