【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 }
