【HDOJ】3275 Light

这就是个简单线段树+延迟标记。因为对bool使用了~而不是！，wa了一下午找不到原因。

  1 /* 3275 */
  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 typedef struct {
 44     bool f;
 45     int ln, tot;
 46 } node_t;
 47
 48 const int maxn = 1e5+5;
 49 char s[maxn];
 50 node_t nd[maxn<<2];
 51 int L, R;
 52
 53 inline void PushUp(int rt) {
 54     nd[rt].ln = nd[rt<<1].ln + nd[rt<<1|1].ln;
 55 }
 56
 57 inline void PushDown(int rt) {
 58     if (nd[rt].f) {
 59         int lb = rt<<1;
 60         int rb = lb|1;
 61         nd[lb].f = !nd[lb].f;
 62         nd[lb].ln = nd[lb].tot - nd[lb].ln;
 63         nd[rb].f = !nd[rb].f;
 64         nd[rb].ln = nd[rb].tot - nd[rb].ln;
 65         nd[rt].f = false;
 66     }
 67 }
 68
 69 void Build(int l, int r, int rt) {
 70     nd[rt].f = false;
 71     nd[rt].tot = r - l + 1;
 72     if (l == r) {
 73         nd[rt].ln = (s[l] == ‘1‘);
 74         return ;
 75     }
 76
 77     int mid = (l + r) >> 1;
 78     Build(lson);
 79     Build(rson);
 80
 81     PushUp(rt);
 82 }
 83
 84 int Query(int l, int r, int rt) {
 85     if (l == r)
 86         return l;
 87
 88     PushDown(rt);
 89     int mid = (l + r) >> 1;
 90     int ret;
 91
 92     if (nd[rt<<1].ln == nd[rt<<1].tot)
 93         ret = Query(rson);
 94     else
 95         ret = Query(lson);
 96     PushUp(rt);
 97
 98     return ret;
 99 }
100
101 void Update(int l, int r, int rt) {
102     if (L<=l && R>=r) {
103         nd[rt].f = !nd[rt].f;
104         nd[rt].ln = nd[rt].tot - nd[rt].ln;
105         return ;
106     }
107
108     PushDown(rt);
109     int mid = (l + r) >> 1;
110
111     if (R <= mid) {
112         Update(lson);
113     } else if (L > mid) {
114         Update(rson);
115     } else {
116         Update(lson);
117         Update(rson);
118     }
119
120     PushUp(rt);
121 }
122
123 int main() {
124     ios::sync_with_stdio(false);
125     #ifndef ONLINE_JUDGE
126         freopen("data.in", "r", stdin);
127         freopen("data.out", "w", stdout);
128     #endif
129
130     int n, l;
131     int ans, k;
132
133     while (scanf("%d %d",&n,&l)!=EOF && (n||l)) {
134         scanf("%s", s+1);
135         Build(1, n, 1);
136         if (nd[1].tot == nd[1].ln) {
137             puts("0");
138             continue;
139         }
140         if (l == 0) {
141             puts("-1");
142             continue;
143         }
144
145         ans = 0;
146         while (1) {
147             ++ans;
148             k = Query(1, n, 1);
149             L = k;
150             R = L + l - 1;
151             #ifndef ONLINE_JUDGE
152                 // printf("k = %d\n", k);
153             #endif
154             if (R > n) {
155                 ans = -1;
156                 break;
157             }
158             Update(1, n, 1);
159             if (nd[1].tot == nd[1].ln)
160                 break;
161         }
162         printf("%d\n", ans);
163     }
164
165     #ifndef ONLINE_JUDGE
166         printf("time = %d.\n", (int)clock());
167     #endif
168
169     return 0;
170 }