HDOJ 3397 Sequence operation

难在异或对询问区间最大连续1长度的影响,每次异或时,把异或标记更新到底(cover标记不为-1),直接更新当前最大连续1区间的长度。
  1 # include <stdio.h>
  2 
  3 # define N 100005
  4 
  5 # define ls ((r)<<1)
  6 # define rs ((r)<<1|1)
  7 # define mid (((x)+(y))>>1)
  8 
  9 int n, m, a[N];
 10 int cover[N<<2];
 11 int sum[N<<2], lcon[N<<2], rcon[N<<2], tcon[N<<2];
 12 
 13 int Max(int x, int y)
 14 {
 15     return x > y ? x : y;
 16 }
 17 
 18 int Min(int x, int y)
 19 {
 20     return x < y ? x : y;
 21 }
 22 
 23 void update(int r, int x, int y)
 24 {
 25     sum[r] = sum[ls] + sum[rs];
 26     lcon[r] = lcon[ls], rcon[r] = rcon[rs];
 27     if (lcon[ls] == mid-x+1) lcon[r] += lcon[rs];
 28     if (rcon[rs] == y-mid) rcon[r] += rcon[ls];
 29     tcon[r] = Max(rcon[ls]+lcon[rs], Max(tcon[ls], tcon[rs]));
 30 }
 31 
 32 void pushdown(int r, int x, int y)
 33 {
 34     if (cover[r] != -1)
 35     {
 36         cover[ls] = cover[rs] = cover[r];
 37         sum[ls] = (cover[r] ? mid-x+1:0);
 38         sum[rs] = (cover[r] ? y-mid:0);
 39         lcon[ls] = rcon[ls] = tcon[ls] = sum[ls];
 40         lcon[rs] = rcon[rs] = tcon[rs] = sum[rs];
 41         cover[r] = -1;
 42     }
 43 }
 44 
 45 void build(int r, int x, int y)
 46 {
 47     cover[r] = -1;
 48     if (x == y)
 49     {
 50         cover[r] = sum[r] = a[x];
 51         lcon[r] = rcon[r] = tcon[r] = a[x];
 52         return ;
 53     }
 54     build(ls, x, mid);
 55     build(rs, mid+1, y);
 56     update(r, x, y);
 57 }
 58 
 59 void change(int r, int x, int y, int s, int t, int val)
 60 {
 61     if (s<=x && y<=t)
 62     {
 63         cover[r] = val;
 64         sum[r] = (val ? y-x+1:0);
 65         lcon[r] = rcon[r] = tcon[r] = sum[r];
 66         return ;
 67     }
 68     pushdown(r, x, y);
 69     if (s <= mid) change(ls, x, mid, s, t, val);
 70     if (mid+1<=t) change(rs, mid+1, y, s, t, val);
 71     update(r, x, y);
 72 }
 73 
 74 void query_sum(int r, int x, int y, int s, int t, int *ans)
 75 {
 76     if (s<=x && y<=t)
 77     {
 78         *ans += sum[r];
 79         return ;
 80     }
 81     pushdown(r, x, y);
 82     if (s <= mid) query_sum(ls, x, mid, s, t, ans);
 83     if (mid+1<=t) query_sum(rs, mid+1, y, s, t, ans);
 84 }
 85 
 86 /******************************************************/
 87 void procxor(int r, int x, int y, int s, int t)
 88 {
 89     if (s<=x && y<=t)
 90     {
 91         if (cover[r] != -1)
 92         {
 93             cover[r] ^= 1;
 94             sum[r] = (cover[r] ? y-x+1:0);
 95             lcon[r] = rcon[r] = tcon[r] = sum[r];
 96             return ;
 97         }
 98     }
 99     pushdown(r, x, y);
100     if (s <= mid) procxor(ls, x, mid, s, t);
101     if (mid+1 <= t) procxor(rs, mid+1, y, s, t);
102     update(r, x, y);
103 }
104 
105 int query_len(int r, int x, int y, int s, int t)
106 {
107     int a, b, c;
108     if (s==x && y==t) return tcon[r];
109     pushdown(r, x, y);
110     if (t <= mid) return query_len(ls, x, mid, s, t);
111     else if (s >= mid+1) return query_len(rs, mid+1, y, s, t);
112     else
113     {
114         a = query_len(ls, x, mid, s, mid);
115         b = query_len(rs, mid+1, y, mid+1, t);
116         c = Min(rcon[ls], mid-s+1)+Min(lcon[rs], t-mid);
117         return Max(a, Max(b, c));
118     }
119 }
120 /******************************************************/
121 void solve(void)
122 {
123     int i, op, s, t, ans;
124     scanf("%d%d", &n, &m);
125     for (i = 1; i <= n; ++i) scanf("%d", &a[i]);
126     build(1, 1, n);
127     for (i = 1; i <= m; ++i)
128     {
129         scanf("%d%d%d", &op, &s, &t), ++s, ++t;
130         switch(op)
131         {
132             case 0: change(1, 1, n, s, t, 0); break;
133             case 1: change(1, 1, n, s, t, 1); break;
134             case 2: procxor(1, 1, n, s, t); break;
135             case 3: ans = 0, query_sum(1, 1, n, s, t, &ans), printf("%d\n", ans); break;
136             case 4: ans = query_len(1, 1, n, s, t), printf("%d\n", ans); break;
137         }
138     }
139 }
140 
141 int main()
142 {
143     int T;
144     scanf("%d", &T);
145     while (T--)    solve();
146     return 0;
147 }

  

原文地址:https://www.cnblogs.com/JMDWQ/p/2654532.html