划分树模板题目，主席树也可解。
划分树。
1 /* 4251 */
2 #include <iostream>
3 #include <sstream>
4 #include <string>
5 #include <map>
6 #include <queue>
7 #include <set>
8 #include <stack>
9 #include <vector>
10 #include <deque>
11 #include <algorithm>
12 #include <cstdio>
13 #include <cmath>
14 #include <ctime>
15 #include <cstring>
16 #include <climits>
17 #include <cctype>
18 #include <cassert>
19 #include <functional>
20 #include <iterator>
21 #include <iomanip>
22 using namespace std;
23 //#pragma comment(linker,"/STACK:102400000,1024000")
24
25 #define sti set<int>
26 #define stpii set<pair<int, int> >
27 #define mpii map<int,int>
28 #define vi vector<int>
29 #define pii pair<int,int>
30 #define vpii vector<pair<int,int> >
31 #define rep(i, a, n) for (int i=a;i<n;++i)
32 #define per(i, a, n) for (int i=n-1;i>=a;--i)
33 #define clr clear
34 #define pb push_back
35 #define mp make_pair
36 #define fir first
37 #define sec second
38 #define all(x) (x).begin(),(x).end()
39 #define SZ(x) ((int)(x).size())
40 #define lson l, mid, rt<<1
41 #define rson mid+1, r, rt<<1|1
42
43 const int maxn = 1e5+5;
44 int order[maxn];
45 int toLeft[18][maxn];
46 int val[18][maxn];
47 int n;
48
49 void Build(int l, int r, int dep) {
50 if (l == r) {
51 toLeft[dep][l] = toLeft[dep][l-1] + 1;
52 return ;
53 }
54
55 int mid = (l + r) >> 1;
56 int same = mid - l + 1;
57
58 rep(i, l, r+1) {
59 if (val[dep][i] < order[mid])
60 --same;
61 }
62
63 int lpos = l, rpos = mid + 1;
64
65 rep(i, l, r+1) {
66 if (val[dep][i] < order[mid]) {
67 val[dep+1][lpos++] = val[dep][i];
68 } else if (val[dep][i]==order[mid] && same>0) {
69 val[dep+1][lpos++] = val[dep][i];
70 --same;
71 } else {
72 val[dep+1][rpos++] = val[dep][i];
73 }
74 toLeft[dep][i] = toLeft[dep][l-1] + lpos - l;
75 }
76
77 Build(l, mid, dep+1);
78 Build(mid+1, r, dep+1);
79 }
80
81 int Query(int l, int r, int k, int L, int R, int dep) {
82 if (l == r) {
83 return val[dep][l];
84 }
85
86 int mid = (L + R) >> 1;
87 int tmp = toLeft[dep][r] - toLeft[dep][l-1];
88
89 if (tmp >= k) {
90 int ll = L + toLeft[dep][l-1] - toLeft[dep][L-1];
91 int rr = ll + tmp - 1;
92
93 return Query(ll, rr, k, L, mid, dep+1);
94 } else {
95 k -= tmp;
96 int ll = mid+1 + l-L - (toLeft[dep][l-1] - toLeft[dep][L-1]);
97 int rr = ll + (r-l+1-tmp) - 1;
98
99 return Query(ll, rr, k, mid+1, R, dep+1);
100 }
101 }
102
103 void solve() {
104 sort(order+1, order+1+n);
105 Build(1, n, 0);
106
107 int q;
108 int l, r, kth;
109 int ans;
110
111 scanf("%d", &q);
112 while (q--) {
113 scanf("%d %d", &l, &r);
114 kth = ((l+r)>>1) - l + 1;
115 ans = Query(l, r, kth, 1, n, 0);
116 printf("%d\n", ans);
117 }
118 }
119
120 int main() {
121 ios::sync_with_stdio(false);
122 #ifndef ONLINE_JUDGE
123 freopen("data.in", "r", stdin);
124 freopen("data.out", "w", stdout);
125 #endif
126
127 int t = 0;
128
129 while (scanf("%d", &n)!=EOF) {
130 rep(i, 1, n+1) {
131 scanf("%d", &val[0][i]);
132 order[i] = val[0][i];
133 }
134 printf("Case %d:\n", ++t);
135 solve();
136 }
137
138 #ifndef ONLINE_JUDGE
139 printf("time = %d.\n", (int)clock());
140 #endif
141
142 return 0;
143 }
主席树。
1 /* 4251 */
2 #include <iostream>
3 #include <sstream>
4 #include <string>
5 #include <map>
6 #include <queue>
7 #include <set>
8 #include <stack>
9 #include <vector>
10 #include <deque>
11 #include <algorithm>
12 #include <cstdio>
13 #include <cmath>
14 #include <ctime>
15 #include <cstring>
16 #include <climits>
17 #include <cctype>
18 #include <cassert>
19 #include <functional>
20 #include <iterator>
21 #include <iomanip>
22 using namespace std;
23 //#pragma comment(linker,"/STACK:102400000,1024000")
24
25 #define sti set<int>
26 #define stpii set<pair<int, int> >
27 #define mpii map<int,int>
28 #define vi vector<int>
29 #define pii pair<int,int>
30 #define vpii vector<pair<int,int> >
31 #define rep(i, a, n) for (int i=a;i<n;++i)
32 #define per(i, a, n) for (int i=n-1;i>=a;--i)
33 #define clr clear
34 #define pb push_back
35 #define mp make_pair
36 #define fir first
37 #define sec second
38 #define all(x) (x).begin(),(x).end()
39 #define SZ(x) ((int)(x).size())
40 // #define lson l, mid, rt<<1
41 // #define rson mid+1, r, rt<<1|1
42
43 const int maxn = 1e5+5;
44 const int maxm = maxn * 20;
45 int a[maxn], b[maxn];
46 int T[maxn];
47 int lson[maxm], rson[maxm], c[maxm];
48 int n, m, tot;
49
50 void init() {
51 m = tot = 0;
52 }
53
54 int Build(int l, int r) {
55 int rt = tot++;
56
57 c[rt] = 0;
58 if (l == r)
59 return rt;
60
61 int mid = (l + r) >> 1;
62
63 lson[rt] = Build(l, mid);
64 rson[rt] = Build(mid+1, r);
65 return rt;
66 }
67
68 int Insert(int rt, int p, int delta) {
69 int nrt = tot++, ret = nrt;
70 int l = 0, r = m - 1, mid;
71
72 c[nrt] = c[rt] + delta;
73 while (l < r) {
74 mid = (l + r) >> 1;
75 if (p <= mid) {
76 lson[nrt] = tot++;
77 rson[nrt] = rson[rt];
78 nrt = lson[nrt];
79 rt = lson[rt];
80 r = mid;
81 } else {
82 lson[nrt] = lson[rt];
83 rson[nrt] = tot++;
84 nrt = rson[nrt];
85 rt = rson[rt];
86 l = mid + 1;
87 }
88 c[nrt] = c[rt] + delta;
89 }
90
91 return ret;
92 }
93
94 int Query(int lrt, int rrt, int k, int l, int r) {
95 if (l == r)
96 return l;
97
98 int mid = (l + r) >> 1;
99 int tmp = c[lson[rrt]] - c[lson[lrt]];
100
101 if (tmp >= k) {
102 return Query(lson[lrt], lson[rrt], k, l, mid);
103 } else {
104 k -= tmp;
105 return Query(rson[lrt], rson[rrt], k, mid+1, r);
106 }
107 }
108
109 void solve() {
110 init();
111 sort(b, b+n);
112 m = unique(b, b+n) - b;
113 T[0] = Build(0, m-1);
114 rep(i, 0, n) {
115 int id = lower_bound(b, b+m, a[i]) - b;
116 T[i+1] = Insert(T[i], id, 1);
117 }
118
119 int q;
120 int l, r, kth;
121 int ans;
122
123 scanf("%d", &q);
124 while (q--) {
125 scanf("%d %d", &l, &r);
126 kth = ((l+r)>>1)-l+1;
127 int id = Query(T[l-1], T[r], kth, 0, m-1);
128 ans = b[id];
129 printf("%d\n", ans);
130 }
131 }
132
133 int main() {
134 ios::sync_with_stdio(false);
135 #ifndef ONLINE_JUDGE
136 freopen("data.in", "r", stdin);
137 freopen("data.out", "w", stdout);
138 #endif
139
140 int t = 0;
141
142 while (scanf("%d", &n)!=EOF) {
143 rep(i, 0, n) {
144 scanf("%d", &a[i]);
145 b[i] = a[i];
146 }
147 printf("Case %d:\n", ++t);
148 solve();
149 }
150
151 #ifndef ONLINE_JUDGE
152 printf("time = %d.\n", (int)clock());
153 #endif
154
155 return 0;
156 }
时间： 2024-10-05 19:11:55