线段树：
1 #include<cstdio> 2 #define INF 987654321 3 #define MAXN 200010 4 int tree[MAXN << 2]; 5 inline int MAX(int x, int y) { 6 return x > y ? x : y; 7 } 8 inline void PushUp(int rt) { 9 tree[rt] = MAX(tree[rt << 1], tree[rt << 1 | 1]); 10 } 11 void Build(int L, int R, int rt) { 12 if (L == R) 13 scanf("%d", &tree[rt]); 14 else { 15 int mid = (L + R) >> 1; 16 Build(L, mid, rt << 1); 17 Build(mid + 1, R, rt << 1 | 1); 18 PushUp(rt); 19 } 20 } 21 void Update(int x, int val, int L, int R, int rt) { 22 if (L == R) 23 tree[rt] = val; 24 else { 25 int mid; 26 mid = (L + R) >> 1; 27 if (mid >= x) 28 Update(x, val, L, mid, rt << 1); 29 else 30 Update(x, val, mid + 1, R, rt << 1 | 1); 31 PushUp(rt); 32 } 33 } 34 int Query(int x, int y, int L, int R, int rt) { 35 if (x <= L && R <= y) 36 return tree[rt]; 37 int ans, mid; 38 ans = -INF; 39 mid = (L + R) >> 1; 40 if (x <= mid) 41 ans = MAX(ans, Query(x, y, L, mid, rt << 1)); 42 if (y > mid) 43 ans = MAX(ans, Query(x, y, mid + 1, R, rt << 1 | 1)); 44 return ans; 45 } 46 int main() { 47 int n, m, x, y; 48 char ch; 49 while (~scanf("%d%d", &n, &m)) { 50 Build(1, n, 1); 51 while (m--) { 52 scanf(" %c%d%d", &ch, &x, &y); 53 if (ch == 'Q') 54 printf("%d\n", Query(x, y, 1, n, 1)); 55 else 56 Update(x, y, 1, n, 1); 57 } 58 } 59 return 0; 60 }
Splay：
1 #include<cstdio> 2 #include<algorithm> 3 #define INF 987654321 4 #define MAXN 300000 5 using namespace std; 6 struct SplayTree { 7 int root; 8 int next[MAXN][2], key[MAXN], pre[MAXN], res[MAXN]; 9 inline void PushUp(int x) { 10 res[x] = max(res[next[x][0]], res[next[x][1]]); 11 res[x] = max(res[x], key[x]); 12 } 13 void NewNode(int val, int x) { 14 next[x][0] = next[x][1] = 0; 15 key[x] = res[x] = val; 16 pre[x] = x - 1; 17 next[x - 1][1] = x; 18 } 19 inline void Rotate(int x, int kind) { 20 int y, z; 21 y = pre[x]; 22 z = pre[y]; 23 next[y][!kind] = next[x][kind]; 24 pre[next[x][kind]] = y; 25 next[z][next[z][1] == y] = x; 26 pre[x] = z; 27 next[x][kind] = y; 28 pre[y] = x; 29 PushUp(y); 30 PushUp(x); 31 } 32 void Splay(int x, int goal) { 33 if (x != goal) { 34 while (pre[x] != goal) { 35 if (next[pre[x]][0] == x) 36 Rotate(x, 1); 37 else 38 Rotate(x, 0); 39 } 40 if (!goal) 41 root = x; 42 } 43 } 44 void Update(int x, int val) { 45 x++; 46 Splay(x, 0); 47 key[x] = val; 48 PushUp(x); 49 } 50 void Query(int x, int y) { 51 y += 2; 52 Splay(x, 0); 53 Splay(y, x); 54 printf("%d\n", res[next[y][0]]); 55 } 56 } tree; 57 int main() { 58 char ch; 59 int n, q; 60 int i, x, y; 61 while (~scanf("%d%d", &n, &q)) { 62 tree.NewNode(-INF, 1); 63 for (i = 0; i < n; i++) { 64 scanf("%d", &x); 65 tree.NewNode(x, i + 2); 66 } 67 tree.NewNode(-INF, n + 2); 68 for (i = n + 2; i; i--) 69 tree.PushUp(i); 70 tree.root = 1; 71 while (q--) { 72 scanf(" %c%d%d", &ch, &x, &y); 73 if (ch == 'Q') 74 tree.Query(x, y); 75 else 76 tree.Update(x, y); 77 } 78 } 79 return 0; 80 }
