线段树模板

线段树区间更新：

//0 x y v: [x,y]内元素都加上v //1 x y: [x,y]内元素的和 typedef long long ll; const int N = 100010; struct node { int l, r; ll val, mark; }tr[N*4]; int cas = 0; void push_up(int k) { tr[k].val = tr[k<<1].val + tr[k<<1|1].val; } void push_down(int k) { if(tr[k].mark) { tr[k<<1].mark += tr[k].mark, tr[k<<1|1].mark += tr[k].mark; tr[k<<1].val += (tr[k<<1].r - tr[k<<1].l + 1) * tr[k].mark; tr[k<<1|1].val += (tr[k<<1|1].r - tr[k<<1|1].l + 1) * tr[k].mark; tr[k].mark = 0; } } void build(int l, int r, int k) { tr[k].l = l, tr[k].r = r, tr[k].mark = 0; if(l == r) { tr[k].val = 0; return; } int mid = (l + r) >> 1; build(l, mid, k << 1); build(mid + 1, r, k << 1|1); push_up(k); } void update(int l, int r, int val, int k) { if(l <= tr[k].l && tr[k].r <= r) { tr[k].mark += val; tr[k].val += 1LL * (tr[k].r - tr[k].l + 1) * val; return; } push_down(k); int mid = (tr[k].l + tr[k].r) >> 1; if(l <= mid) update(l, r, val, k << 1); if(r > mid) update(l, r, val, k << 1|1); push_up(k); } ll query(int l, int r, int k) { if(l <= tr[k].l && tr[k].r <= r) return tr[k].val; push_down(k); int mid = (tr[k].l + tr[k].r) >> 1; ll res = 0; if(l <= mid) res += query(l, r, k << 1); if(r > mid) res += query(l, r, k << 1|1); return res; } int main() { int t, n, m, a, b, c, d; scanf("%d", &t); while(t--) { scanf("%d%d", &n, &m); build(1, n, 1); printf("Case %d:\n", ++cas); for(int i = 0; i < m; i++) { scanf("%d", &a); if(a == 0) {//下标从0开始，故+1 scanf("%d%d%d", &b, &c, &d); update(b+1, c+1, d, 1); } else { scanf("%d%d", &b, &c); printf("%lld\n", query(b+1, c+1, 1)); } } } return 0; }

线段树区间合并：

#include <bits/stdc++.h> using namespace std; //给定一个长度为n的01串，接下来一个m，有m个操作，操作有两种：0 a b查询区间内最长连续1的长度，1 a b反转区间内，0变1，1变0 const int N = 100010; struct node { int l, r; int lone, lzero, rone, rzero, max1, max0;//分别维护左起1，左起0，右起1，右起0，区间中1的最大长度，0的最大长度 int len, mark; //区间长度，lazy标记 }tr[N*4]; int val[N]; void push_up(int k) { tr[k].lone = tr[k<<1].lone; if(tr[k<<1].lone == tr[k<<1].len) tr[k].lone += tr[k<<1|1].lone;//左子树左起1的长度等于区间长度，那么直接加上右子树的左起1长度 tr[k].lzero = tr[k<<1].lzero; if(tr[k<<1].lzero == tr[k<<1].len) tr[k].lzero += tr[k<<1|1].lzero; tr[k].rone = tr[k<<1|1].rone; if(tr[k<<1|1].rone == tr[k<<1|1].len) tr[k].rone += tr[k<<1].rone; tr[k].rzero = tr[k<<1|1].rzero; if(tr[k<<1|1].rzero == tr[k<<1|1].len) tr[k].rzero += tr[k<<1].rzero; tr[k].max1 = max(tr[k<<1].rone + tr[k<<1|1].lone, max(tr[k<<1].max1, tr[k<<1|1].max1)); tr[k].max0 = max(tr[k<<1].rzero + tr[k<<1|1].lzero, max(tr[k<<1].max0, tr[k<<1|1].max0)); } void push_down(int k) { if(tr[k].mark)//0与1互变，所以所有的维护信息也要互换 { tr[k<<1].mark ^= tr[k].mark; tr[k<<1|1].mark ^= tr[k].mark; swap(tr[k<<1].lone, tr[k<<1].lzero); swap(tr[k<<1].rone, tr[k<<1].rzero); swap(tr[k<<1].max1, tr[k<<1].max0); swap(tr[k<<1|1].lone, tr[k<<1|1].lzero); swap(tr[k<<1|1].rone, tr[k<<1|1].rzero); swap(tr[k<<1|1].max1, tr[k<<1|1].max0); tr[k].mark = 0; } } void build(int l, int r, int k) { tr[k].l = l, tr[k].r = r, tr[k].mark = 0, tr[k].len = r - l + 1; if(l == r) { if(val[l]) tr[k].lone = tr[k].rone = tr[k].max1 = 1, tr[k].lzero = tr[k].rzero = tr[k].max0 = 0; else tr[k].lzero = tr[k].rzero = tr[k].max0 = 1, tr[k].lone = tr[k].rone = tr[k].max1 = 0; return; } int mid = (tr[k].l + tr[k].r) >> 1; build(l, mid, k << 1); build(mid + 1, r, k << 1 | 1); push_up(k); } void update(int l, int r, int k) { if(l <= tr[k].l && tr[k].r <= r) { tr[k].mark ^= 1; swap(tr[k].rone, tr[k].rzero); swap(tr[k].lone, tr[k].lzero); swap(tr[k].max1, tr[k].max0); return; } push_down(k); int mid = (tr[k].l + tr[k].r) >> 1; if(l <= mid) update(l, r, k << 1); if(r > mid) update(l, r, k << 1 | 1); push_up(k); } int query(int l, int r, int k) { if(l == tr[k].l && tr[k].r == r) return tr[k].max1; push_down(k); int mid = (tr[k].l + tr[k].r) >> 1; if(r <= mid) return query(l, r, k << 1); //查询区间位于左子树 else if(l > mid) return query(l, r, k << 1 | 1); //查询区间位于右子树 else //查询区间被分割 { int left = 0, right = 0, midd = 0; midd = min(mid - l + 1, tr[k<<1].rone) + min(r - mid, tr[k<<1|1].lone); left = query(l, mid, k << 1); right = query(mid + 1, r, k << 1 | 1); return max(midd, max(left, right)); } } int main() { int n, m, a, b, c; while(~ scanf("%d", &n)) { for(int i = 1; i <= n; i++) scanf("%d", val + i); build(1, n, 1); scanf("%d", &m); for(int i = 0; i < m; i++) { scanf("%d%d%d", &a, &b, &c); if(a) update(b, c, 1); else printf("%d\n", query(b, c, 1)); } } return 0; }