//只限于查找已经排好序得数组
int min=0;
int max=arg.length-1;
while (min<=max) {
int temp = (min + max) / 2;
if (t == arg[temp]) {
return temp;
}else if (t > arg[temp]) {
min = temp + 1;
}else if(t < arg[temp]) {
max = temp - 1;
}
}
return -1;
}