new file: P3870.cpp

.gitignore

@@ -3,3 +3,4 @@
 !.gitignore
 !README.md
 !*.md
+tmp.md

P3870.cpp

@@ -0,0 +1,73 @@
+#include <bits/stdc++.h>
+using namespace std;
+struct node
+{
+    int l, r, num;
+    bool lazy_tag;
+} seg[400005];
+void init(int now, int l, int r)
+{
+    seg[now].l = l, seg[now].r = r;
+    if (l == r)
+        return;
+    int mid = (l + r) >> 1;
+    init(now * 2, l, mid);
+    init(now * 2 + 1, mid + 1, r);
+}
+void apply(int now)
+{
+    seg[now].num = seg[now].r - seg[now].l + 1 - seg[now].num;
+    seg[now].lazy_tag = !seg[now].lazy_tag;
+}
+void pushdown(int now)
+{
+    if (!seg[now].lazy_tag)
+        return;
+    apply(now * 2);
+    apply(now * 2 + 1);
+    seg[now].lazy_tag = false;
+}
+void modify(int now, int l, int r)
+{
+    if (l <= seg[now].l && r >= seg[now].r)
+    {
+        apply(now);
+        return;
+    }
+    pushdown(now);
+    int mid = (seg[now].l + seg[now].r) >> 1;
+    if (l <= mid)
+        modify(now * 2, l, r);
+    if (r > mid)
+        modify(now * 2 + 1, l, r);
+    seg[now].num = seg[now * 2].num + seg[now * 2 + 1].num;
+}
+int query(int now, int l, int r)
+{
+    if (l <= seg[now].l && r >= seg[now].r)
+        return seg[now].num;
+    pushdown(now);
+    int mid = (seg[now].l + seg[now].r) >> 1;
+    int answer = 0;
+    if (l <= mid)
+        answer += query(now * 2, l, r);
+    if (r > mid)
+        answer += query(now * 2 + 1, l, r);
+    return answer;
+}
+int n, m;
+int main()
+{
+    scanf("%d%d", &n, &m);
+    init(1, 1, n);
+    while (m--)
+    {
+        int c, l, r;
+        scanf("%d%d%d", &c, &l, &r);
+        if (c == 0)
+            modify(1, l, r);
+        else
+            printf("%d\n", query(1, l, r));
+    }
+    return 0;
+}